Hello everyone, I met the problem below: can someone help me, please?

PS E:\hexo\blog> hexo deploy
INFO Deploying: git
INFO Setting up Git deployment...
events.js:141
>throw er; // Unhandled 'error' event
>^

Error: spawn git ENOENT
>at exports._errnoException (util.js:837:11)
>at Process.ChildProcess._handle.onexit (internal/child_process.js:178:32)
>at onErrorNT (internal/child_process.js:344:16)
>at doNTCallback2 (node.js:429:9)
>at process._tickCallback (node.js:343:17)

The version of npm is 2.14.2.

The part _config.yml is below

Docs: http://hexo.io/docs/deployment.html
deploy:
>type: git
>repository: https://github.com/xiaoliuzi/xiaoliuzi.github.io.git
>branch: master

and I have tried to execute the command , and I also create another new folder, but it doesn't work.
npm install hexo-deployer-git --save

Please help me. Thank you.