diff --git a/backend/ai_services/services.py b/backend/ai_services/services.py
index 0ceca94..367360b 100644
--- a/backend/ai_services/services.py
+++ b/backend/ai_services/services.py
@@ -58,9 +58,10 @@ class AliyunTingwuService:
             self.client = None
             logger.warning("Aliyun AccessKey configuration missing.")
 
-    def upload_to_oss(self, file_obj, file_name):
+    def upload_to_oss(self, file_obj, file_name, day=7):
         """
-        上传文件到 OSS 并返回带签名的 URL (有效期 3 小时)
+        上传文件到 OSS 并返回带签名的 URL
+        默认生成有效期为 7 天 (3600 * 24 * day) 的签名URL，方便评委在一段时间内都能播放。
         """
         if not self.bucket:
             raise Exception("OSS Client not initialized")
@@ -70,8 +71,8 @@ class AliyunTingwuService:
             # file_obj 应该是打开的文件对象或字节流
             self.bucket.put_object(file_name, file_obj)
             
-            # 生成签名 URL，有效期 3 小时 (3600 * 3)
-            url = self.bucket.sign_url('GET', file_name, 3600 * 3)
+            # 生成签名 URL，有效期 7 天 (3600 * 24 * 7 = 604800 秒)
+            url = self.bucket.sign_url('GET', file_name, 3600 * 24 * day)
             return url
         except Exception as e:
             logger.error(f"OSS Upload failed: {e}")
diff --git a/backend/competition/templates/judge/dashboard.html b/backend/competition/templates/judge/dashboard.html
index a945c29..9965de3 100644
--- a/backend/competition/templates/judge/dashboard.html
+++ b/backend/competition/templates/judge/dashboard.html
@@ -2,6 +2,23 @@
 
 {% block title %}项目列表 - 评委系统{% endblock %}
 
+{% block extra_css %}
+<style>
+.markdown-body p { margin-bottom: 0.5em; }
+.markdown-body ul { list-style-type: disc; padding-left: 1.5em; margin-bottom: 0.5em; }
+.markdown-body ol { list-style-type: decimal; padding-left: 1.5em; margin-bottom: 0.5em; }
+.markdown-body strong { font-weight: 600; }
+.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4 { font-weight: 600; margin-top: 1em; margin-bottom: 0.5em; }
+.markdown-body { overflow: hidden; }
+.line-clamp-5 {
+    display: -webkit-box;
+    -webkit-line-clamp: 5;
+    -webkit-box-orient: vertical;
+    overflow: hidden;
+}
+</style>
+{% endblock %}
+
 {% block content %}
 <div class="flex flex-col sm:flex-row justify-between items-center mb-8 gap-4">
     <div>
@@ -104,7 +121,12 @@
                         <div class="p-4 bg-white space-y-4">
                             <div>
                                 <p class="text-xs font-semibold text-gray-500 uppercase mb-1">AI 总结</p>
-                                <p class="text-sm text-gray-800" id="modalAiSummary"></p>
+                                <div class="relative">
+                                    <div class="text-sm text-gray-800 markdown-body line-clamp-5 transition-all duration-300" id="modalAiSummary"></div>
+                                    <button id="toggleAiSummaryBtn" type="button" onclick="toggleAiSummary()" class="text-xs text-blue-600 hover:text-blue-800 focus:outline-none flex items-center mt-2 hidden">
+                                        <i class="fas fa-chevron-down mr-1" id="toggleAiSummaryIcon"></i> <span id="toggleAiSummaryText">点击完整显示</span>
+                                    </button>
+                                </div>
                             </div>
                             <div class="border-t border-gray-100 pt-3 relative">
                                 <div class="flex justify-between items-center mb-1">
@@ -248,7 +270,28 @@
 {% endblock %}
 
 {% block extra_js %}
+<script src="https://cdn.jsdelivr.net/npm/marked/marked.min.js"></script>
 <script>
+/**
+ * 切换 AI 总结内容的显示状态（折叠/展开）
+ * 通过添加或移除 line-clamp-5 类来实现截断或完整显示，并更新按钮的文字和图标。
+ */
+function toggleAiSummary() {
+    const summaryDiv = document.getElementById('modalAiSummary');
+    const toggleText = document.getElementById('toggleAiSummaryText');
+    const toggleIcon = document.getElementById('toggleAiSummaryIcon');
+    
+    if (summaryDiv.classList.contains('line-clamp-5')) {
+        summaryDiv.classList.remove('line-clamp-5');
+        toggleText.innerText = '收起内容';
+        toggleIcon.className = 'fas fa-chevron-up mr-1';
+    } else {
+        summaryDiv.classList.add('line-clamp-5');
+        toggleText.innerText = '点击完整显示';
+        toggleIcon.className = 'fas fa-chevron-down mr-1';
+    }
+}
+
 function updateFileName(input) {
     const display = document.getElementById('fileNameDisplay');
     if (input.files.length > 0) {
@@ -359,7 +402,29 @@ async function viewProject(id) {
         const aiSection = document.getElementById('aiResultSection');
         if (data.ai_result) {
             aiSection.style.display = 'block';
-            document.getElementById('modalAiSummary').innerText = (data.ai_result.summary || '暂无总结').substring(0, 300) + (data.ai_result.summary && data.ai_result.summary.length > 300 ? '...' : '');
+            
+            const summaryDiv = document.getElementById('modalAiSummary');
+            const toggleBtn = document.getElementById('toggleAiSummaryBtn');
+            const toggleText = document.getElementById('toggleAiSummaryText');
+            const toggleIcon = document.getElementById('toggleAiSummaryIcon');
+            
+            const summaryText = data.ai_result.summary || '暂无总结';
+            summaryDiv.innerHTML = marked.parse(summaryText);
+            
+            // Reset to collapsed state
+            summaryDiv.classList.add('line-clamp-5');
+            toggleText.innerText = '点击完整显示';
+            toggleIcon.className = 'fas fa-chevron-down mr-1';
+            
+            // Show/hide toggle button based on content height
+            setTimeout(() => {
+                if (summaryDiv.scrollHeight > summaryDiv.clientHeight) {
+                    toggleBtn.classList.remove('hidden');
+                } else {
+                    toggleBtn.classList.add('hidden');
+                }
+            }, 50);
+            
             document.getElementById('modalAiTrans').innerText = (data.ai_result.transcription || '暂无内容').substring(0, 150) + '...';
             
             // Store full data for full transcription modal