diff --git a/go/543-Diameter-of-Binary-Tree.go b/go/543-Diameter-of-Binary-Tree.go
new file mode 100644
index 000000000..73051e637
--- /dev/null
+++ b/go/543-Diameter-of-Binary-Tree.go
@@ -0,0 +1,32 @@
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func diameterOfBinaryTree(root *TreeNode) int {
+	maxLength := 0
+	dfs(root, &maxLength)
+	return maxLength
+}
+
+func dfs(t *TreeNode, maxLength *int) int {
+	if t == nil {
+		return 0
+	}
+
+	left := dfs(t.Left, maxLength)
+	right := dfs(t.Right, maxLength)
+	*maxLength = max(*maxLength, left+right)
+
+	return max(left, right) + 1
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
\ No newline at end of file