diff --git a/templates/create_certificate.html b/templates/create_certificate.html
index eaec94a..ac60955 100644
--- a/templates/create_certificate.html
+++ b/templates/create_certificate.html
@@ -8,7 +8,7 @@
         <h4 class="card-title">创建新证书</h4>
     </div>
     <div class="card-body">
-        <form method="POST" action="{{ url_for('create_certificate_view') }}">
+        <form method="POST" action="{{ url_for('create_certificate_view') }}" id="certificateForm">
             <div class="row mb-3">
                 <div class="col-md-6">
                     <label for="common_name" class="form-label">通用名(CN)</label>
@@ -57,12 +57,24 @@
 
             <div class="row mb-3">
                 <div class="col-md-6">
-                    <label for="san_dns" class="form-label">SAN DNS (可选)</label>
+                    <label for="san_dns" class="form-label">
+                        SAN DNS (可选)
+                        <span class="text-primary ms-1" data-bs-toggle="tooltip"
+                              title="Subject Alternative Name - 主题备用名称，用于指定证书可用的多个域名">
+                            <i class="fas fa-question-circle"></i>
+                        </span>
+                    </label>
                     <input type="text" class="form-control" id="san_dns" name="san_dns">
                     <div class="form-text">多个DNS用逗号分隔，如: example.com,www.example.com</div>
                 </div>
                 <div class="col-md-6">
-                    <label for="san_ip" class="form-label">SAN IP (可选)</label>
+                    <label for="san_ip" class="form-label">
+                        SAN IP (可选)
+                        <span class="text-primary ms-1" data-bs-toggle="tooltip"
+                              title="Subject Alternative Name - 主题备用名称，用于指定证书可用的多个IP地址">
+                            <i class="fas fa-question-circle"></i>
+                        </span>
+                    </label>
                     <input type="text" class="form-control" id="san_ip" name="san_ip">
                     <div class="form-text">多个IP用逗号分隔，如: 192.168.1.1,10.0.0.1</div>
                 </div>
@@ -90,4 +102,65 @@
         </form>
     </div>
 </div>
+
+<!-- SAN 警告模态框 -->
+<div class="modal fade" id="sanWarningModal" tabindex="-1" aria-labelledby="sanWarningModalLabel" aria-hidden="true">
+    <div class="modal-dialog">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h5 class="modal-title" id="sanWarningModalLabel">缺少SAN扩展警告</h5>
+                <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
+            </div>
+            <div class="modal-body">
+                <p>您没有配置任何SAN(主题备用名称)扩展，这可能导致以下问题：</p>
+                <ul>
+                    <li>现代浏览器可能不信任没有SAN扩展的证书</li>
+                    <li>证书只能通过Common Name(CN)字段指定的名称访问</li>
+                    <li>不符合现代安全标准</li>
+                </ul>
+                <p>建议至少配置一个DNS SAN或IP SAN。</p>
+            </div>
+            <div class="modal-footer">
+                <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">返回修改</button>
+                <button type="button" class="btn btn-primary" id="continueWithoutSan">继续创建</button>
+            </div>
+        </div>
+    </div>
+</div>
+
+{% endblock %}
+
+{% block scripts %}
+{{ super() }}
+<script>
+// 初始化工具提示
+document.addEventListener('DOMContentLoaded', function() {
+    // 初始化Bootstrap工具提示
+    var tooltipTriggerList = [].slice.call(document.querySelectorAll('[data-bs-toggle="tooltip"]'))
+    var tooltipList = tooltipTriggerList.map(function (tooltipTriggerEl) {
+        return new bootstrap.Tooltip(tooltipTriggerEl)
+    })
+
+    // 表单提交验证
+    document.getElementById('certificateForm').addEventListener('submit', function(e) {
+        const sanDns = document.getElementById('san_dns').value.trim()
+        const sanIp = document.getElementById('san_ip').value.trim()
+
+        // 检查是否没有配置任何SAN
+        if (!sanDns && !sanIp) {
+            e.preventDefault() // 阻止表单提交
+
+            // 显示警告模态框
+            var sanWarningModal = new bootstrap.Modal(document.getElementById('sanWarningModal'))
+            sanWarningModal.show()
+
+            // 继续创建按钮事件
+            document.getElementById('continueWithoutSan').addEventListener('click', function() {
+                sanWarningModal.hide()
+                document.getElementById('certificateForm').submit()
+            })
+        }
+    })
+})
+</script>
 {% endblock %}
\ No newline at end of file