diff --git a/40.implement-Bubble-Sort.md b/40.implement-Bubble-Sort.md
new file mode 100644
index 0000000..86ce6e5
--- /dev/null
+++ b/40.implement-Bubble-Sort.md
@@ -0,0 +1,56 @@
+# 40. implement Bubble Sort
+Bubble Sort is a simple comparison-based sorting algorithm. It repeatedly steps through the list, compares adjacent elements, and swaps them if they are in the wrong order. This process continues until the list is sorted.
+
+
+### Problem
+
+https://bigfrontend.dev/problem/implement-Bubble-Sort
+
+#
+
+### Problem Description
+
+Even for Front-End Engineer, it is a must to understand how basic sorting algorithms work.
+
+Now you are asked to implement [Bubble Sort](https://en.wikipedia.org/wiki/Bubble_sort), which sorts an integer array in ascending order.
+
+Do it **in-place**, no need to return anything.
+
+**Follow-up**
+
+What is time cost for average / worst case ? Is it stable?
+
+#
+
+### Solution
+
+```js
+/**
+ * @param {number[]} arr
+ */
+function bubbleSort(arr) {
+  let hasNoSwaps;
+  for (let i = arr.length; i >= 0; i--) {
+    hasNoSwaps = true;
+    for (let j = 0; j < i - 1; j++) {
+      if (arr[j] > arr[j + 1]) {
+        [arr[j], arr[j + 1]] = [arr[j + 1], arr[j]];
+        hasNoSwaps = false;
+      }
+    }
+    if (hasNoSwaps) {
+      break;
+    }
+  }
+}
+
+// Usage 
+console.log(bubbleSort([37, 45, 29, 8, 12, 88, -3])); // [-3, 8, 12, 29, 37, 45, 88]
+console.log(bubbleSort([8, 1, 2, 3, 4, 5, 6, 7])); // [1, 2, 3, 4, 5, 6, 7, 8]
+console.log(bubbleSort([1, 2, 3, 4, 5, 6, 7, 8])); // [1, 2, 3, 4, 5, 6, 7, 8]
+```
+
+#### Use Cases:
+
+1. **Small Data Sets**: It can be useful for small datasets or when the simplicity of the implementation is more critical than performance.
+2. **Nearly Sorted Data**: If the data is nearly sorted or has only a few elements out of order, Bubble Sort can be efficient.