diff --git a/min_depth_tree.js b/min_depth_tree.js
new file mode 100644
index 0000000..a360b51
--- /dev/null
+++ b/min_depth_tree.js
@@ -0,0 +1,22 @@
+function minDepth(root){
+    if(!root) return 0;
+    let depth = 1;
+    if(!root.left && !root.right) return depth;
+    let queue = [root];
+    
+    while(queue.length>0){
+        let len = queue.length;
+        for(let i = 0; i < len; i++){
+            root = queue.shift();
+            if(!root.left&&!root.right) return depth;
+            else{
+                // root.left ? queue.push(root.left) : null;
+                // root.right? queue.push(root.right): null;
+                if(root.left) queue.push(root.left);
+                if(root.right) queue.push(root.right)
+            }
+        }
+        depth++;
+    }
+    return depth;
+}