diff --git a/backend/app/config.py b/backend/app/config.py
index 5c49d92..f353cc6 100644
--- a/backend/app/config.py
+++ b/backend/app/config.py
@@ -82,6 +82,13 @@ class Settings:
     S2S_BUILD_RETRIES = int(_env("DPM_S2S_BUILD_RETRIES", "4"))
     S2S_BUILD_RETRY_DELAY = float(_env("DPM_S2S_BUILD_RETRY_DELAY", "10"))
     S2S_LOG_LEVEL = _env("DPM_S2S_LOG_LEVEL", "INFO").upper()
+    # 语音助手基础提示词（.env 设 DPM_S2S_INSTRUCTIONS 可覆盖；知识库内容由 rag 自动拼接）
+    S2S_INSTRUCTIONS = _env(
+        "DPM_S2S_INSTRUCTIONS",
+        "你是 PineSound 园区智能语音助手。可用工具：get_park_overview（园区实时数据）、"
+        "query_companies（企业名录）、control_display（大屏控制）、get_time（时间）。"
+        "涉及园区数据/企业/大屏控制时务必调用工具获取准确信息。请用简洁专业的中文回答，不超过三句话。",
+    )
 
 
 
diff --git a/backend/app/rag.py b/backend/app/rag.py
index 815920b..bb1e661 100644
--- a/backend/app/rag.py
+++ b/backend/app/rag.py
@@ -100,3 +100,16 @@ def brief(max_chars: int = 1200) -> str:
         out.append(c)
         total += len(c)
     return "\n\n".join(out)
+
+
+def build_instructions() -> str:
+    """语音助手的完整基础提示词 = 配置提示词 + 园区知识库摘要（服务端统一组装）"""
+    from .config import settings
+    base = settings.S2S_INSTRUCTIONS.strip()
+    try:
+        kb = brief()
+        if kb:
+            base += f"\n\n【园区知识库】\n{kb}"
+    except Exception as e:  # noqa: BLE001
+        log.warning("rag: 知识库拼接失败（仅用基础提示词）: %s", e)
+    return base
diff --git a/backend/app/routers.py b/backend/app/routers.py
index c34e33e..e839428 100644
--- a/backend/app/routers.py
+++ b/backend/app/routers.py
@@ -465,3 +465,13 @@ def kb_retrieve(q: str = "", top_k: int = 3):
     except Exception as e:  # noqa: BLE001
         log.warning("kb retrieve 失败: %s", e)
         return {"ok": False, "error": str(e)}
+
+@router.get("/api/s2s/instructions")
+def s2s_instructions():
+    """语音助手基础提示词（服务端统一组装：配置提示词 + 园区知识库）"""
+    try:
+        from .rag import build_instructions
+        return {"ok": True, "instructions": build_instructions()}
+    except Exception as e:  # noqa: BLE001
+        log.warning("s2s instructions 构建失败: %s", e)
+        return {"ok": False, "error": str(e)}
diff --git a/src/pages/VoiceAssistant.jsx b/src/pages/VoiceAssistant.jsx
index 679ae83..9a4c305 100644
--- a/src/pages/VoiceAssistant.jsx
+++ b/src/pages/VoiceAssistant.jsx
@@ -16,7 +16,9 @@ import './voice-original.css';
 import './voice-overrides.css';
 
 const VOICE_URL = window.__DPM_VOICE_WS__ || `ws://${window.location.hostname}:8765/v1/realtime`;
-const DEFAULT_INSTRUCTIONS = '你是 PineSound 园区智能语音助手。可用工具：get_park_overview（园区实时数据）、query_companies（企业名录）、control_display（大屏控制）、get_time（时间）。涉及园区数据/企业/大屏控制时务必调用工具获取准确信息。请用简洁专业的中文回答，不超过三句话。';
+// 基础提示词由后端统一管理（GET /api/s2s/instructions：配置提示词 + 园区知识库），
+// 前端不硬编码；此处仅为后端不可用时的兜底
+const FALLBACK_INSTRUCTIONS = '你是 PineSound 园区智能语音助手，请用简洁专业的中文回答，不超过三句话。';
 const DEFAULT_VOICE = 'Cherry';
 const DEFAULT_GATE_DB = -50;
 
@@ -316,15 +318,13 @@ export default function VoiceAssistant() {
       if (!audioCtxRef.current) audioCtxRef.current = new AudioContext();
       if (audioCtxRef.current.state === 'suspended') await audioCtxRef.current.resume();
 
-      // 知识库：拉取园区知识摘要拼进 instructions（静态知识一次注入；失败不影响对话）
-      let instructions = DEFAULT_INSTRUCTIONS;
+      // 基础提示词：从后端拉取（配置 + 园区知识库已由服务端组装）；失败用极简兜底
+      let instructions = FALLBACK_INSTRUCTIONS;
       try {
-        const kbRes = await fetch(`${API_BASE}/api/kb/brief`, { cache: 'no-store' });
-        const kbData = await kbRes.json();
-        if (kbData?.ok && kbData.brief) {
-          instructions = `${DEFAULT_INSTRUCTIONS}\n\n【园区知识库】\n${kbData.brief}`;
-        }
-      } catch { /* 知识库不可用不影响对话 */ }
+        const insRes = await fetch(`${API_BASE}/api/s2s/instructions`, { cache: 'no-store' });
+        const insData = await insRes.json();
+        if (insData?.ok && insData.instructions) instructions = insData.instructions;
+      } catch { /* 后端不可用不影响对话 */ }
 
       const client = new S2sWsRealtimeClient({
         directUrl: VOICE_URL,