diff --git a/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java b/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java
index 1857aaf..2e6347d 100644
--- a/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java
+++ b/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java
@@ -38,6 +38,7 @@ public class RedisCacheEnhanceTemplate {
 
     public RedisCacheEnhanceTemplate(StringRedisTemplate redis, CacheKeyBuilder keyBuilder,
                                      CacheValueCodec codec, RedisCacheProperties props) {
+        validateProps(props);
         this.redis = redis;
         this.keyBuilder = keyBuilder;
         this.codec = codec;
@@ -134,6 +135,39 @@ public class RedisCacheEnhanceTemplate {
         }
     }
 
+    /** 构造期校验配置项,误配在装配阶段即 fail-fast,而非运行期才暴露。 */
+    private static void validateProps(RedisCacheProperties props) {
+        if (props.getDefaultTtlSeconds() <= 0) {
+            throw new IllegalArgumentException(
+                    "redis-cache.default-ttl-seconds must be positive, but was " + props.getDefaultTtlSeconds());
+        }
+        if (props.getNullTtlSeconds() <= 0) {
+            throw new IllegalArgumentException(
+                    "redis-cache.null-ttl-seconds must be positive, but was " + props.getNullTtlSeconds());
+        }
+        double ratio = props.getJitterRatio();
+        if (ratio < 0 || ratio >= 1) {
+            throw new IllegalArgumentException(
+                    "redis-cache.jitter-ratio must be in [0,1), but was " + ratio);
+        }
+        RedisCacheProperties.Breakdown bd = props.getBreakdown();
+        if (bd == null) {
+            throw new IllegalArgumentException("redis-cache.breakdown must not be null");
+        }
+        if (bd.getLockTtlMs() <= 0) {
+            throw new IllegalArgumentException(
+                    "redis-cache.breakdown.lock-ttl-ms must be positive, but was " + bd.getLockTtlMs());
+        }
+        if (bd.getWaitTimeoutMs() < 0) {
+            throw new IllegalArgumentException(
+                    "redis-cache.breakdown.wait-timeout-ms must be >= 0, but was " + bd.getWaitTimeoutMs());
+        }
+        if (bd.getWaitIntervalMs() <= 0) {
+            throw new IllegalArgumentException(
+                    "redis-cache.breakdown.wait-interval-ms must be positive, but was " + bd.getWaitIntervalMs());
+        }
+    }
+
     // ---- 读取或回源(三防核心)----
 
     public <T> T getOrLoad(String key, Class<T> type, Supplier<T> loader) {
diff --git a/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java b/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java
index 7e451b2..311f59d 100644
--- a/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java
+++ b/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java
@@ -19,6 +19,7 @@ import org.springframework.data.redis.core.script.RedisScript;
 import java.time.Duration;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -294,4 +295,27 @@ class RedisCacheEnhanceTemplateTest {
         // 中断后立即停止等待:仅首次 tryGet 读一次,而非空转数百次
         verify(valueOps, atMost(2)).get("cache:user:1");
     }
+
+    // ---- #5: 构造期配置 fail-fast 校验 ----
+
+    private RedisCacheEnhanceTemplate newTemplateWith(Consumer<RedisCacheProperties> mut) {
+        RedisCacheProperties p = new RedisCacheProperties();
+        mut.accept(p);
+        return new RedisCacheEnhanceTemplate(redis, keyBuilder, codec, p);
+    }
+
+    @Test
+    void constructorRejectsInvalidProps() {
+        assertThrows(IllegalArgumentException.class, () -> newTemplateWith(p -> p.setDefaultTtlSeconds(0)));
+        assertThrows(IllegalArgumentException.class, () -> newTemplateWith(p -> p.setNullTtlSeconds(-1)));
+        assertThrows(IllegalArgumentException.class, () -> newTemplateWith(p -> p.setJitterRatio(1.0)));
+        assertThrows(IllegalArgumentException.class, () -> newTemplateWith(p -> p.setJitterRatio(-0.1)));
+        assertThrows(IllegalArgumentException.class, () -> newTemplateWith(p -> p.getBreakdown().setLockTtlMs(0)));
+        assertThrows(IllegalArgumentException.class, () -> newTemplateWith(p -> p.getBreakdown().setWaitIntervalMs(0)));
+    }
+
+    @Test
+    void constructorAcceptsDefaults() {
+        new RedisCacheEnhanceTemplate(redis, keyBuilder, codec, new RedisCacheProperties());
+    }
 }