diff --git a/backend/internal/payment/provider/easypay_refund_test.go b/backend/internal/payment/provider/easypay_refund_test.go
index 8d535b5126..730e82feff 100644
--- a/backend/internal/payment/provider/easypay_refund_test.go
+++ b/backend/internal/payment/provider/easypay_refund_test.go
@@ -202,7 +202,7 @@ func TestEasyPayCustomMethodsUseConfiguredUpstreamType(t *testing.T) {
 		"notifyUrl":     "https://example.com/notify",
 		"returnUrl":     "https://example.com/return",
 		"paymentMode":   paymentModePopup,
-		"customMethods": `[{"type":"ldc","upstreamType":"epay","displayName":"LDC"},{"type":"usdt_trc20","upstreamType":"usdt","displayName":"USDT-TRC20"}]`,
+		"customMethods": `[{"type":"ldc","upstreamType":"epay","displayName":"LDC"},{"type":"usdt_trc20","upstreamType":"usdt.trc20","displayName":"USDT-TRC20"}]`,
 	})
 	if err != nil {
 		t.Fatalf("NewEasyPay: %v", err)
@@ -221,8 +221,8 @@ func TestEasyPayCustomMethodsUseConfiguredUpstreamType(t *testing.T) {
 	if err != nil {
 		t.Fatalf("parse pay url: %v", err)
 	}
-	if got := payURL.Query().Get("type"); got != "usdt" {
-		t.Fatalf("pay url type = %q, want usdt (%s)", got, resp.PayURL)
+	if got := payURL.Query().Get("type"); got != "usdt.trc20" {
+		t.Fatalf("pay url type = %q, want usdt.trc20 (%s)", got, resp.PayURL)
 	}
 }
 
diff --git a/backend/internal/service/payment_config_providers.go b/backend/internal/service/payment_config_providers.go
index d1bf2de7aa..b4d8f2b22d 100644
--- a/backend/internal/service/payment_config_providers.go
+++ b/backend/internal/service/payment_config_providers.go
@@ -224,6 +224,7 @@ func validateProviderRequest(providerKey, name, supportedTypes string) error {
 }
 
 var easyPayCustomMethodCodePattern = regexp.MustCompile(`^[a-z0-9_-]+$`)
+var easyPayUpstreamMethodCodePattern = regexp.MustCompile(`^[a-z0-9_.-]+$`)
 
 type easyPayCustomMethodConfig struct {
 	Type         string `json:"type"`
@@ -253,8 +254,8 @@ func validateEasyPayCustomMethods(config map[string]string, supportedTypes strin
 		if !easyPayCustomMethodCodePattern.MatchString(method.Type) {
 			return infraerrors.BadRequest("VALIDATION_ERROR", "customMethods type may only contain lowercase letters, digits, underscores, and hyphens")
 		}
-		if !easyPayCustomMethodCodePattern.MatchString(method.UpstreamType) {
-			return infraerrors.BadRequest("VALIDATION_ERROR", "customMethods upstreamType may only contain lowercase letters, digits, underscores, and hyphens")
+		if !easyPayUpstreamMethodCodePattern.MatchString(method.UpstreamType) {
+			return infraerrors.BadRequest("VALIDATION_ERROR", "customMethods upstreamType may only contain lowercase letters, digits, periods, underscores, and hyphens")
 		}
 		if easyPayCustomMethodTypeConflictsWithBuiltin(method.Type) {
 			return infraerrors.BadRequest("VALIDATION_ERROR", "customMethods type cannot start with alipay or wxpay")
diff --git a/backend/internal/service/payment_config_providers_test.go b/backend/internal/service/payment_config_providers_test.go
index 74fd2a3467..c539449c69 100644
--- a/backend/internal/service/payment_config_providers_test.go
+++ b/backend/internal/service/payment_config_providers_test.go
@@ -128,6 +128,23 @@ func TestValidateEasyPayCustomMethods(t *testing.T) {
 			config:         map[string]string{"customMethods": `[{"type":"ldc","upstreamType":"epay","displayName":"LDC"}]`},
 			supportedTypes: "alipay,wxpay,ldc",
 		},
+		{
+			name:           "upstream type allows periods",
+			config:         map[string]string{"customMethods": `[{"type":"usdt_trc20","upstreamType":"usdt.trc20"}]`},
+			supportedTypes: "alipay,wxpay,usdt_trc20",
+		},
+		{
+			name:           "custom type still rejects periods",
+			config:         map[string]string{"customMethods": `[{"type":"usdt.trc20","upstreamType":"usdt.trc20"}]`},
+			supportedTypes: "alipay,wxpay,usdt.trc20",
+			wantErr:        "customMethods type may only contain lowercase letters",
+		},
+		{
+			name:           "upstream type still rejects slashes",
+			config:         map[string]string{"customMethods": `[{"type":"usdt_trc20","upstreamType":"usdt/trc20"}]`},
+			supportedTypes: "alipay,wxpay,usdt_trc20",
+			wantErr:        "customMethods upstreamType may only contain lowercase letters",
+		},
 		{
 			name:           "malformed custom methods json",
 			config:         map[string]string{"customMethods": `not-json`},
diff --git a/frontend/src/components/payment/PaymentProviderDialog.vue b/frontend/src/components/payment/PaymentProviderDialog.vue
index 73724bbf5f..7743e4073a 100644
--- a/frontend/src/components/payment/PaymentProviderDialog.vue
+++ b/frontend/src/components/payment/PaymentProviderDialog.vue
@@ -759,7 +759,7 @@ function validateEasyPayCustomMethods(): string | null {
     if (!/^[a-z0-9_-]+$/.test(method.type)) {
       return t('admin.settings.payment.validationEasyPayCustomMethodTypeInvalid')
     }
-    if (!/^[a-z0-9_-]+$/.test(method.upstreamType)) {
+    if (!/^[a-z0-9_.-]+$/.test(method.upstreamType)) {
       return t('admin.settings.payment.validationEasyPayCustomMethodUpstreamTypeInvalid')
     }
     if ((PROVIDER_SUPPORTED_TYPES.easypay || []).includes(method.type)) {
diff --git a/frontend/src/components/payment/__tests__/PaymentProviderDialog.spec.ts b/frontend/src/components/payment/__tests__/PaymentProviderDialog.spec.ts
index 2596952d67..18ca4cb483 100644
--- a/frontend/src/components/payment/__tests__/PaymentProviderDialog.spec.ts
+++ b/frontend/src/components/payment/__tests__/PaymentProviderDialog.spec.ts
@@ -166,7 +166,7 @@ describe('PaymentProviderDialog payment guide', () => {
     expect(payload.config.accountId).toBe('')
   })
 
-  it('serializes EasyPay custom methods and adds them to supported_types', async () => {
+  it.each(['epay', 'usdt.trc20'])('serializes EasyPay upstream type %s and adds the local type to supported_types', async (upstreamType) => {
     const provider = providerFactory({
       provider_key: 'easypay',
       name: 'EasyPay',
@@ -197,7 +197,7 @@ describe('PaymentProviderDialog payment guide', () => {
     }
 
     await ldcTypeInput.setValue('ldc')
-    await upstreamTypeInput.setValue('epay')
+    await upstreamTypeInput.setValue(upstreamType)
     await displayNameInput.setValue('LDC')
     await wrapper.find('form').trigger('submit.prevent')
 
@@ -205,11 +205,15 @@ describe('PaymentProviderDialog payment guide', () => {
       config: Record<string, string>
       supported_types: string[]
     }
-    expect(payload.config.customMethods).toBe('[{"type":"ldc","upstreamType":"epay","displayName":"LDC"}]')
+    expect(JSON.parse(payload.config.customMethods)).toEqual([{ type: 'ldc', upstreamType, displayName: 'LDC' }])
     expect(payload.supported_types).toEqual(['alipay', 'wxpay', 'ldc'])
   })
 
-  it('rejects custom EasyPay method types with built-in payment prefixes', async () => {
+  it.each([
+    ['alipay_hk', 'hkpay'],
+    ['usdt.trc20', 'usdt.trc20'],
+    ['usdt_trc20', 'usdt/trc20'],
+  ])('rejects invalid EasyPay mapping %s to %s', async (type, upstreamType) => {
     const provider = providerFactory({
       provider_key: 'easypay',
       name: 'EasyPay',
@@ -239,9 +243,9 @@ describe('PaymentProviderDialog payment guide', () => {
       throw new Error('custom method inputs not found')
     }
 
-    await typeInput.setValue('alipay_hk')
-    await upstreamTypeInput.setValue('hkpay')
-    await displayNameInput.setValue('Hong Kong Alipay')
+    await typeInput.setValue(type)
+    await upstreamTypeInput.setValue(upstreamType)
+    await displayNameInput.setValue('Custom payment')
     await wrapper.find('form').trigger('submit.prevent')
 
     expect(wrapper.emitted('save')).toBeUndefined()
diff --git a/frontend/src/i18n/locales/en/admin/settings.ts b/frontend/src/i18n/locales/en/admin/settings.ts
index eb5c74dfe3..88f5e1d760 100644
--- a/frontend/src/i18n/locales/en/admin/settings.ts
+++ b/frontend/src/i18n/locales/en/admin/settings.ts
@@ -759,7 +759,7 @@ export default {
         validationFieldRequired: '{field} is required',
         validationEasyPayCustomMethodRequired: 'Each custom EasyPay method requires both a payment type and an upstream type',
         validationEasyPayCustomMethodTypeInvalid: 'Custom EasyPay payment types may only contain lowercase letters, digits, underscores, and hyphens',
-        validationEasyPayCustomMethodUpstreamTypeInvalid: 'EasyPay upstream types may only contain lowercase letters, digits, underscores, and hyphens',
+        validationEasyPayCustomMethodUpstreamTypeInvalid: 'EasyPay upstream types may only contain lowercase letters, digits, periods, underscores, and hyphens',
         validationEasyPayCustomMethodReserved: 'Custom EasyPay payment types cannot use built-in alipay or wxpay',
         validationEasyPayCustomMethodPrefixReserved: 'Custom EasyPay payment types cannot start with alipay or wxpay',
         validationEasyPayCustomMethodDuplicate: 'Custom EasyPay payment types must be unique',
diff --git a/frontend/src/i18n/locales/zh/admin/settings.ts b/frontend/src/i18n/locales/zh/admin/settings.ts
index 5e0db540b0..85b9701c3c 100644
--- a/frontend/src/i18n/locales/zh/admin/settings.ts
+++ b/frontend/src/i18n/locales/zh/admin/settings.ts
@@ -754,7 +754,7 @@ export default {
         validationFieldRequired: '{field} 不能为空',
         validationEasyPayCustomMethodRequired: '每个易支付自定义方式都必须填写支付方式和上游 type',
         validationEasyPayCustomMethodTypeInvalid: '易支付自定义支付方式只能包含小写字母、数字、下划线和短横线',
-        validationEasyPayCustomMethodUpstreamTypeInvalid: '易支付上游 type 只能包含小写字母、数字、下划线和短横线',
+        validationEasyPayCustomMethodUpstreamTypeInvalid: '易支付上游 type 只能包含小写字母、数字、点号、下划线和短横线',
         validationEasyPayCustomMethodReserved: '易支付自定义支付方式不能使用内置的 alipay 或 wxpay',
         validationEasyPayCustomMethodPrefixReserved: '易支付自定义支付方式不能以 alipay 或 wxpay 开头',
         validationEasyPayCustomMethodDuplicate: '易支付自定义支付方式不能重复',