diff --git a/Algorithms/0307. Range Sum Query - Mutable/307. Range Sum Query - Mutable.go b/Algorithms/0307. Range Sum Query - Mutable/307. Range Sum Query - Mutable.go
new file mode 100644
index 00000000..5b84a304
--- /dev/null
+++ b/Algorithms/0307. Range Sum Query - Mutable/307. Range Sum Query - Mutable.go	
@@ -0,0 +1,63 @@
+package leetcode
+
+import (
+	"github.com/halfrost/LeetCode-Go/template"
+)
+
+// Constructor307 define
+func Constructor307(nums []int) NumArray {
+	st := template.SegmentTree{}
+	st.Init(nums, func(i, j int) int {
+		return i + j
+	})
+	return NumArray{st: &st}
+}
+
+// Update define
+func (this *NumArray) Update(i int, val int) {
+	this.st.Update(i, val)
+}
+
+//解法二 prefixSum，sumRange 时间复杂度 O(1)
+
+// // NumArray define
+// type NumArray307 struct {
+// 	prefixSum []int
+// 	data   []int
+// }
+
+// // Constructor307 define
+// func Constructor307(nums []int) NumArray307 {
+// 	data := make([]int, len(nums))
+// 	for i := 0; i < len(nums); i++ {
+// 		data[i] = nums[i]
+// 	}
+// 	for i := 1; i < len(nums); i++ {
+// 		nums[i] += nums[i-1]
+// 	}
+// 	return NumArray307{prefixSum: nums, data: data}
+// }
+
+// // Update define
+// func (this *NumArray307) Update(i int, val int) {
+// 	this.data[i] = val
+// 	this.prefixSum[0] = this.data[0]
+// 	for i := 1; i < len(this.data); i++ {
+// 		this.prefixSum[i] = this.prefixSum[i-1] + this.data[i]
+// 	}
+// }
+
+// // SumRange define
+// func (this *NumArray307) SumRange(i int, j int) int {
+// 	if i > 0 {
+// 		return this.prefixSum[j] - this.prefixSum[i-1]
+// 	}
+// 	return this.prefixSum[j]
+// }
+
+/**
+ * Your NumArray object will be instantiated and called as such:
+ * obj := Constructor(nums);
+ * obj.Update(i,val);
+ * param_2 := obj.SumRange(i,j);
+ */
diff --git a/Algorithms/0307. Range Sum Query - Mutable/307. Range Sum Query - Mutable_test.go b/Algorithms/0307. Range Sum Query - Mutable/307. Range Sum Query - Mutable_test.go
new file mode 100644
index 00000000..6ea6ccd1
--- /dev/null
+++ b/Algorithms/0307. Range Sum Query - Mutable/307. Range Sum Query - Mutable_test.go	
@@ -0,0 +1,15 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+func Test_Problem307(t *testing.T) {
+	obj := Constructor307([]int{1, 3, 5})
+	fmt.Printf("obj = %v\n", obj)
+	fmt.Printf("SumRange(0,2) = %v\n", obj.SumRange(0, 2))
+	obj.Update(1, 2)
+	fmt.Printf("obj = %v\n", obj)
+	fmt.Printf("SumRange(0,2) = %v\n", obj.SumRange(0, 2))
+}
diff --git a/Algorithms/0307. Range Sum Query - Mutable/README.md b/Algorithms/0307. Range Sum Query - Mutable/README.md
new file mode 100755
index 00000000..6cafb629
--- /dev/null
+++ b/Algorithms/0307. Range Sum Query - Mutable/README.md	
@@ -0,0 +1,50 @@
+# [307. Range Sum Query - Mutable](https://leetcode.com/problems/range-sum-query-mutable/)
+
+
+## 题目:
+
+Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.
+
+The update(i, val) function modifies nums by updating the element at index i to val.
+
+**Example:**
+
+    Given nums = [1, 3, 5]
+    
+    sumRange(0, 2) -> 9
+    update(1, 2)
+    sumRange(0, 2) -> 8
+
+**Note:**
+
+1. The array is only modifiable by the update function.
+2. You may assume the number of calls to update and sumRange function is distributed evenly.
+
+
+## 题目大意
+
+给定一个整数数组  nums，求出数组从索引 i 到 j  (i ≤ j) 范围内元素的总和，包含 i,  j 两点。
+
+update(i, val) 函数可以通过将下标为 i 的数值更新为 val，从而对数列进行修改。
+
+示例:
+
+```
+Given nums = [1, 3, 5]
+
+sumRange(0, 2) -> 9  
+update(1, 2)  
+sumRange(0, 2) -> 8  
+```
+
+说明:
+
+- 数组仅可以在 update 函数下进行修改。
+- 你可以假设 update 函数与 sumRange 函数的调用次数是均匀分布的。
+
+## 解题思路
+
+
+- 给出一个数组，数组里面的数都是`**可变**`的，设计一个数据结构能够满足查询数组任意区间内元素的和。
+- 对比第 303 题，这一题由于数组里面的元素都是**`可变`**的，所以第一个想到的解法就是线段树，构建一颗线段树，父结点内存的是两个子结点的和，初始化建树的时间复杂度是 O(log n)，查询区间元素和的时间复杂度是 O(log n)，更新元素值的时间复杂度是 O(log n)。
+- 如果此题还用 prefixSum 的思路解答呢？那每次 update 操作的时间复杂度都是 O(n)，因为每次更改一个值，最坏情况就是所有的 prefixSum 都要更新一次。prefixSum 的方法在这道题上面也可以 AC，只不过时间排名在 5%，非常差。