diff --git a/dynamic-programming/src/leetcode/editor/cn/FibonacciNumber.java b/dynamic-programming/src/leetcode/editor/cn/FibonacciNumber.java
new file mode 100644
index 0000000..62179e2
--- /dev/null
+++ b/dynamic-programming/src/leetcode/editor/cn/FibonacciNumber.java
@@ -0,0 +1,62 @@
+//<p><strong>斐波那契数</strong>&nbsp;（通常用&nbsp;<code>F(n)</code> 表示）形成的序列称为 <strong>斐波那契数列</strong> 。该数列由&nbsp;<code>0</code> 和 <code>1</code> 开始，后面的每一项数字都是前面两项数字的和。也就是：</p>
+//
+//<pre>
+//F(0) = 0，F(1)&nbsp;= 1
+//F(n) = F(n - 1) + F(n - 2)，其中 n &gt; 1
+//</pre>
+//
+//<p>给定&nbsp;<code>n</code> ，请计算 <code>F(n)</code> 。</p>
+//
+//<p>&nbsp;</p>
+//
+//<p><strong>示例 1：</strong></p>
+//
+//<pre>
+//<strong>输入：</strong>n = 2
+//<strong>输出：</strong>1
+//<strong>解释：</strong>F(2) = F(1) + F(0) = 1 + 0 = 1
+//</pre>
+//
+//<p><strong>示例 2：</strong></p>
+//
+//<pre>
+//<strong>输入：</strong>n = 3
+//<strong>输出：</strong>2
+//<strong>解释：</strong>F(3) = F(2) + F(1) = 1 + 1 = 2
+//</pre>
+//
+//<p><strong>示例 3：</strong></p>
+//
+//<pre>
+//<strong>输入：</strong>n = 4
+//<strong>输出：</strong>3
+//<strong>解释：</strong>F(4) = F(3) + F(2) = 2 + 1 = 3
+//</pre>
+//
+//<p>&nbsp;</p>
+//
+//<p><strong>提示：</strong></p>
+//
+//<ul> 
+// <li><code>0 &lt;= n &lt;= 30</code></li> 
+//</ul>
+//
+//<div><div>Related Topics</div><div><li>递归</li><li>记忆化搜索</li><li>数学</li><li>动态规划</li></div></div><br><div><li>👍 697</li><li>👎 0</li></div>
+package leetcode.editor.cn;
+
+// 509:斐波那契数
+public class FibonacciNumber {
+    public static void main(String[] args) {
+        Solution solution = new FibonacciNumber().new Solution();
+        // TO TEST
+    }
+
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+        public int fib(int n) {
+            return n < 2 ? n : fib(n - 1) + fib(n - 2);
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}
diff --git a/dynamic-programming/src/leetcode/editor/cn/doc/content/FibonacciNumber.md b/dynamic-programming/src/leetcode/editor/cn/doc/content/FibonacciNumber.md
new file mode 100644
index 0000000..8162dff
--- /dev/null
+++ b/dynamic-programming/src/leetcode/editor/cn/doc/content/FibonacciNumber.md
@@ -0,0 +1,44 @@
+<p><strong>斐波那契数</strong>&nbsp;（通常用&nbsp;<code>F(n)</code> 表示）形成的序列称为 <strong>斐波那契数列</strong> 。该数列由&nbsp;<code>0</code> 和 <code>1</code> 开始，后面的每一项数字都是前面两项数字的和。也就是：</p>
+
+<pre>
+F(0) = 0，F(1)&nbsp;= 1
+F(n) = F(n - 1) + F(n - 2)，其中 n &gt; 1
+</pre>
+
+<p>给定&nbsp;<code>n</code> ，请计算 <code>F(n)</code> 。</p>
+
+<p>&nbsp;</p>
+
+<p><strong>示例 1：</strong></p>
+
+<pre>
+<strong>输入：</strong>n = 2
+<strong>输出：</strong>1
+<strong>解释：</strong>F(2) = F(1) + F(0) = 1 + 0 = 1
+</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>n = 3
+<strong>输出：</strong>2
+<strong>解释：</strong>F(3) = F(2) + F(1) = 1 + 1 = 2
+</pre>
+
+<p><strong>示例 3：</strong></p>
+
+<pre>
+<strong>输入：</strong>n = 4
+<strong>输出：</strong>3
+<strong>解释：</strong>F(4) = F(3) + F(2) = 2 + 1 = 3
+</pre>
+
+<p>&nbsp;</p>
+
+<p><strong>提示：</strong></p>
+
+<ul> 
+ <li><code>0 &lt;= n &lt;= 30</code></li> 
+</ul>
+
+<div><div>Related Topics</div><div><li>递归</li><li>记忆化搜索</li><li>数学</li><li>动态规划</li></div></div><br><div><li>👍 697</li><li>👎 0</li></div>
\ No newline at end of file