diff --git a/Altob.NtuInvoiceGateway/Pages/Invoice.cshtml b/Altob.NtuInvoiceGateway/Pages/Invoice.cshtml
index c4857ec..de8a8a5 100644
--- a/Altob.NtuInvoiceGateway/Pages/Invoice.cshtml
+++ b/Altob.NtuInvoiceGateway/Pages/Invoice.cshtml
@@ -42,7 +42,7 @@
                     @if (!string.IsNullOrEmpty(Model.SuccessMessage))
                     {
                         <div class="alert alert-success alert-dismissible fade show" role="alert">
-                            @Model.SuccessMessage 1111
+                            @Model.SuccessMessage
                             <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
                         </div>
                     }
@@ -103,6 +103,15 @@
     </div>
 </div>
 
+<div id="formSubmittingOverlay" class="position-fixed top-0 start-0 w-100 h-100 bg-white bg-opacity-75 d-none" style="z-index: 1050;">
+    <div class="d-flex justify-content-center align-items-center h-100">
+        <div class="text-center">
+            <div class="spinner-border text-primary mb-3" role="status" aria-hidden="true"></div>
+            <p class="fw-semibold mb-0">資料送出中，請稍候...</p>
+        </div>
+    </div>
+</div>
+
 @section Scripts {
     @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
     <script>
@@ -141,7 +150,24 @@
                 return;
             }
 
+            const overlay = document.getElementById('formSubmittingOverlay');
+            const submitButtons = form?.querySelectorAll('button[type="submit"], input[type="submit"]');
+            let isSubmitting = false;
+
+            const lockForm = () => {
+                if (overlay) {
+                    overlay.classList.remove('d-none');
+                }
+                submitButtons?.forEach(btn => btn.disabled = true);
+                isSubmitting = true;
+            };
+
             form.addEventListener('submit', function(event) {
+                if (isSubmitting) {
+                    event.preventDefault();
+                    return;
+                }
+
                 const hasValue = requiredGroup.some(field => field && field.value.trim() !== '');
                 if (!hasValue) {
                     event.preventDefault();
@@ -150,6 +176,7 @@
                 }
 
                 hideError();
+                lockForm();
             });
         });
     </script>