diff --git a/lib/gitremote.js b/lib/gitremote.js
index 812d93b..239d035 100644
--- a/lib/gitremote.js
+++ b/lib/gitremote.js
@@ -93,29 +93,57 @@ exports.getRemoteBranches = function(cwd) {
   return remoteBranches;
 };
 
-var RE_CURRENT_BASE_BRANCHES = /^[ -+]*\*/;
-var RE_BASE_BRANCHE_NAME = /.*?\[([^\]\^~]+).*/; // " +*   [MS170216105211~2^2] test: fixed lint"
+/**
+ * 解析 `git show-branch` 的输出，得到当前分支的基准分支。
+ * @param {String} showBranch 当前分支 `git show-branch` 的输出。
+ * @return {Array} base branch name
+ */
+exports.parseBaseBranchName = function(showBranch) {
+  // 上下上个部分使用 -- 分隔。
+  const info = showBranch.split(/^-+$/m);
+  // 查找当前分支。
+  // -- 上面的部分包含当前分支。
+  const RE_CURRENT_BRANCH = /^(\s*)\*\s+\[([^\]]+)\]/m;
+  const m = RE_CURRENT_BRANCH.exec(info[0]);
+  // 输入异常，没有找到当前分支。
+  if (!m) {
+    return '';
+  }
+  // 当前分支所在的列数
+  const currBranchIndent = m[1].length;
+  const currBranchName = m[2];
+
+  // 从 -- 下面的部分查找当前分支所在列有 *+- 符号的行所在的分支。
+  const brs = info[1].split(/\r\n|\r|\n/);
+  return brs
+    .map(br => {
+      var RE_BASE_BRANCHE_NAME = /^[ *+-]*\[([^\]\^~]+)/; // " +*   [MS170216105211~2^2] test: fixed lint"
+      const m2 = RE_BASE_BRANCHE_NAME.exec(br);
+      // 解析异常，没有找到分支信息，一般是 \n 导致的空行。
+      if (!m2) {
+        return null;
+      }
+      const brName = m2[1];
+      return {
+        brName,
+        currBranchEffect: '*+-'.includes(br.charAt(currBranchIndent)),
+      };
+    })
+    .filter(br => {
+      return br &&
+        br.brName !== currBranchName &&
+        br.currBranchEffect;
+    })
+    .map(br => br.brName);
+};
+
 exports.getBaseBranches = function(cwd) {
-  var cwb = exports.getCurrentBranch(cwd);
-  var baseBranches = child_process.execSync(
+  var showBranch = child_process.execSync(
     'git show-branch --no-color',
     {cwd: cwd}
-  ).toString()
-    .trim()
-    .split(/\r\n|\r|\n/)
-    .filter(function(line) {
-      return RE_CURRENT_BASE_BRANCHES.test(line);
-    })
-    .map(function(line) {
-      var m = RE_BASE_BRANCHE_NAME.exec(line);
-      return m ? m[1] : null;
-    })
-    .filter(function(branchName) {
-      return branchName !== cwb;
-    });
-  // TODO: 获取当前分支的所有祖先分支列表，并按照倒序排列，最近切出的祖先分支排第一。
-  return baseBranches.length >= 0 ? [baseBranches[0]] : [];
-  // return unique(baseBranches);
+  ).toString();
+  const baseBranches = exports.parseBaseBranchName(showBranch);
+  return baseBranches;
 };
 
 // 转义分支名称。
diff --git a/test/gitopen.test.js b/test/gitopen.test.js
index 6dd3fee..42eba77 100644
--- a/test/gitopen.test.js
+++ b/test/gitopen.test.js
@@ -397,6 +397,49 @@ describe('gitremote()', function() {
   it('gitremote.getRemoteName()', function() {
     resolve(gitremote.getRemoteName()).should.be.eql('origin');
   });
+
+
+  describe('gitremote.parseBaseBranchName()', function() {
+    it('gitremote.parseBaseBranchName(1)', function() {
+      const showBranch = `* [feat/hand-guide] feat: hand guide
+ ! [master] sprint_demo_S915482907_20200903_merge_master:Merge branch 'sprint_demo_S915482907_20200903' into 'master'
+  ! [sprint_demo_3_3_S916642948_20201022] PullRequest: something.
+   ! [v3.3] PullRequest: 314 nothing
+----
+*    [feat/hand-guide] feat: hand guide
+ -   [master] sprint_demo_S915482907_20200903_merge_master:Merge branch 'sprint_demo_S915482907_20200903' into 'master'
+---- [sprint_demo_3_3_S916642948_20201022] PullRequest: 314 something`;
+      gitremote.parseBaseBranchName(showBranch).should.be.eql(['sprint_demo_3_3_S916642948_20201022']);
+    });
+
+    it('gitremote.parseBaseBranchName(2)', function() {
+      const showBranch = `! [develop-1] master 2
+ ! [develop-2] feat: 2-1
+  ! [feat/1-1] master 2
+   ! [feat/2-1] feat: 2-1
+    * [feat/2-2] feat: 2-2
+     ! [master] master 2
+------
+    *  [feat/2-2] feat: 2-2
+ + +*  [develop-2] feat: 2-1
+++++*+ [develop-1] master 2`;
+      gitremote.parseBaseBranchName(showBranch).should.be.eql(['develop-2', 'develop-1']);
+    });
+
+    it('gitremote.parseBaseBranchName(3)', function() {
+      const showBranch = `! [develop-1] master 2
+ ! [develop-2] feat: 2-1
+  * [feat/1-1] master 2
+   ! [feat/2-1] feat: 2-1
+    ! [feat/2-2] feat: 2-2
+     ! [master] master 2
+------
+    +  [feat/2-2] feat: 2-2
+ + ++  [develop-2] feat: 2-1
+++*+++ [develop-1] master 2`;
+      gitremote.parseBaseBranchName(showBranch).should.be.eql(['develop-1']);
+    });
+  });
 });
 
 describe('$ cd non-git-dir && gitopen', function() {