diff --git a/src/api/studentTrainingAnswer.js b/src/api/studentTrainingAnswer.js
index d0fce08..8477691 100644
--- a/src/api/studentTrainingAnswer.js
+++ b/src/api/studentTrainingAnswer.js
@@ -170,3 +170,34 @@ export function checkNewProductSurveyStepThree(payload) {
     headers: { repeatSubmit: false },
   });
 }
+
+function validateNewProductSurveyStepFourDemo(form) {
+  const value = form || {};
+  const fields = [
+    ["coreValue", "核心层"],
+    ["tangibleValue", "有形层"],
+    ["extendedValue", "延伸层"],
+  ];
+  for (const [field, label] of fields) {
+    if (!String(value[field] || "").trim()) {
+      throw new Error(`请填写${label}AI应用价值分析`);
+    }
+  }
+  return { valid: true, message: "校验通过" };
+}
+
+export function checkNewProductSurveyStepFour(form) {
+  if (isStudentDemo()) {
+    try {
+      return Promise.resolve({ code: 200, data: validateNewProductSurveyStepFourDemo(form) });
+    } catch (error) {
+      return Promise.reject(error);
+    }
+  }
+  return request({
+    url: "/api/student-training-answers/new-product-survey/step-4/validate",
+    method: "post",
+    data: form,
+    headers: { repeatSubmit: false },
+  });
+}
diff --git a/src/views/foundation/new-product-survey.vue b/src/views/foundation/new-product-survey.vue
index 774d2b0..a2d532a 100644
--- a/src/views/foundation/new-product-survey.vue
+++ b/src/views/foundation/new-product-survey.vue
@@ -197,19 +197,19 @@
               </div>
               <span class="step-chip">价值判断</span>
             </div>
-            <p class="step-desc">根据上面分析，围绕核心层、有形层、延伸层回答以下问题，并形成产品开发启发。</p>
+            <p class="step-desc">结合上面实训，针对AI技术在产品中的应用价值进行分析，回答以下问题。</p>
 
             <label class="field-block">
-              <span>核心层价值：AI 技术解决了用户什么真实问题？</span>
-              <textarea v-model="step4Form.coreValue" class="input-field" rows="5" />
+              <span><b>（1）核心层：</b>AI技术是否实现产品功能突破？是否形成差异化卖点？</span>
+              <textarea v-model="step4Form.coreValue" class="input-field step4-input" rows="7" placeholder="请填写核心层AI应用价值分析" />
             </label>
             <label class="field-block">
-              <span>有形层价值：哪些功能、设计或参数最能体现差异化？</span>
-              <textarea v-model="step4Form.tangibleValue" class="input-field" rows="5" />
+              <span><b>（2）有形层：</b>AI技术是否影响产品形态？如产品外形包装、电商主图设计、参数配置、价格带定位。</span>
+              <textarea v-model="step4Form.tangibleValue" class="input-field step4-input" rows="7" placeholder="请填写有形层AI应用价值分析" />
             </label>
             <label class="field-block">
-              <span>延伸层价值：哪些服务、内容、生态或售后能增强竞争优势？</span>
-              <textarea v-model="step4Form.extendedValue" class="input-field" rows="5" />
+              <span><b>（3）延伸层：</b>AI技术如何通过服务升级、内容更新提升用户粘性，推动付费服务？</span>
+              <textarea v-model="step4Form.extendedValue" class="input-field step4-input" rows="7" placeholder="请填写延伸层AI应用价值分析" />
             </label>
           </div>
         </section>
@@ -230,9 +230,9 @@
         </div>
 
         <div class="task-actions">
-          <button type="button" class="btn-nav btn-submit" :disabled="saving" @click="submitTask">
+          <button type="button" class="btn-nav btn-submit" :disabled="saving || checking" @click="submitTask">
             <el-icon><CircleCheck /></el-icon>
-            提交任务
+            {{ checking ? "正在提交" : "提交任务" }}
           </button>
           <button type="button" class="btn-nav" :disabled="saving" @click="resetExample">
             <el-icon><RefreshLeft /></el-icon>
@@ -270,7 +270,7 @@ import {
   TrendCharts,
 } from "@element-plus/icons-vue";
 import { getTrainingTaskByKey } from "@/api/trainingTask";
-import { checkNewProductSurveyStepOne, checkNewProductSurveyStepThree, checkNewProductSurveyStepTwo, getStudentTrainingAnswer, saveStudentTrainingAnswer, uploadStudentTrainingFile } from "@/api/studentTrainingAnswer";
+import { checkNewProductSurveyStepFour, checkNewProductSurveyStepOne, checkNewProductSurveyStepThree, checkNewProductSurveyStepTwo, getStudentTrainingAnswer, saveStudentTrainingAnswer, uploadStudentTrainingFile } from "@/api/studentTrainingAnswer";
 import useUserStore from "@/store/modules/user";
 import { extractTrainingStepNames } from "@/views/training/taskKeyMap";
 import TrainingAiSidebar from "@/views/components/TrainingAiSidebar.vue";
@@ -709,8 +709,16 @@ function saveCurrentProgress() {
   return saveAnswer("IN_PROGRESS");
 }
 
-function submitTask() {
-  return saveAnswer("SUBMITTED");
+async function submitTask() {
+  checking.value = true;
+  try {
+    await checkNewProductSurveyStepFour(step4Form.value);
+    await saveAnswer("SUBMITTED");
+  } catch (error) {
+    proxy?.$modal?.msgWarning(error?.message || "请完成三层次AI应用价值分析");
+  } finally {
+    checking.value = false;
+  }
 }
 
 async function nextStep() {
@@ -1271,6 +1279,10 @@ function exportOutcome() {
   line-height: 1.65;
 }
 
+.step4-input {
+  min-height: 168px;
+}
+
 .input-single {
   min-height: 42px;
   padding: 0 14px;
diff --git a/tests/new-product-survey-step-one.static.test.cjs b/tests/new-product-survey-step-one.static.test.cjs
index b2440cf..91dc8e7 100644
--- a/tests/new-product-survey-step-one.static.test.cjs
+++ b/tests/new-product-survey-step-one.static.test.cjs
@@ -29,6 +29,11 @@ assert.match(page, /step2Form\.productName \|\| '所选产品'/, "step three mus
 assert.match(page, /countStepThreePoints\(row\.analysis\)/, "step three must show the number of entered analysis points");
 assert.match(page, /checkNewProductSurveyStepThree\(buildStepThreeValidationPayload\(\)\)/, "step three must validate its rows before advancing");
 assert.match(api, /new-product-survey\/step-3\/validate/, "the student API must call the step-three validation endpoint");
+assert.match(page, /AI技术是否实现产品功能突破？是否形成差异化卖点？/, "step four must show the core-layer prototype question");
+assert.match(page, /AI技术是否影响产品形态？如产品外形包装、电商主图设计、参数配置、价格带定位。/, "step four must show the tangible-layer prototype question");
+assert.match(page, /AI技术如何通过服务升级、内容更新提升用户粘性，推动付费服务？/, "step four must show the extended-layer prototype question");
+assert.match(page, /checkNewProductSurveyStepFour\(step4Form\.value\)/, "step four must validate before submission");
+assert.match(api, /new-product-survey\/step-4\/validate/, "the student API must call the step-four validation endpoint");
 assert.match(materialButton, /下载案例资料/, "the download button must use a fixed student-facing label");
 assert.doesNotMatch(materialButton, /\{\{ material\?\.name \|\| "案例文档" \}\}/, "the upload file name must not become button text");