diff --git a/problems/0509.斐波那契数.md b/problems/0509.斐波那契数.md
index d8020d83..c6ce76c0 100644
--- a/problems/0509.斐波那契数.md
+++ b/problems/0509.斐波那契数.md
@@ -245,6 +245,38 @@ var fib = function(n) {
 };
 ```
 
+### C
+动态规划:
+```c
+int fib(int n){
+    //当n <= 1时，返回n
+    if(n <= 1)
+        return n;
+    //动态开辟一个int数组，大小为n+1
+    int *dp = (int *)malloc(sizeof(int) * (n + 1));
+    //设置0号位为0，1号为为1
+    dp[0] = 0;
+    dp[1] = 1;
+
+    //从前向后遍历数组(i=2; i <= n; ++i),下标为n时的元素为dp[i-1] + dp[i-2]
+    int i;
+    for(i = 2; i <= n; ++i) {
+        dp[i] = dp[i - 1] + dp[i - 2];
+    }
+    return dp[n];
+}
+```
+
+递归实现：
+```c
+int fib(int n){
+    //若n小于等于1，返回n
+    if(n <= 1)
+        return n;
+    //否则返回fib(n-1) + fib(n-2)
+    return fib(n-1) + fib(n-2);
+}
+```
 
 
 -----------------------