方法一 命令行输入npm config edit可以调出.npmrc文件（npm userconfig file）。通过修改里面的register可以修改npm镜像站点。
方法二 使用nrm（NPM registry manager）
nrm
NPM registry manager can help you easy and fast switch between different npm registries, now include: cnpm, taobao, nj(nodejitsu), rednpm, edunpm
Install
$ npm install -g nrm
Example
$ nrm ls
* npm ----- https://registry.npmjs.org/
cnpm ---- http://r.cnpmjs.org/
taobao -- https://registry.npm.taobao.org/
nj ------ https://registry.nodejitsu.com/
rednpm -- http://registry.mirror.cqupt.edu.cn
skimdb -- https://skimdb.npmjs.com/registry
$ nrm use cnpm //switch registry to cnpm
Registry has been set to: http://r.cnpmjs.org/
Usage
Usage: nrm [options] [command]
Commands:
ls List all the registries
use <registry> Change registry to registry
add <registry> <url> [home] Add one custom registry
del <registry> Delete one custom registry
home <registry> [browser] Open the homepage of registry with optional browser
test [registry] Show the response time for one or all registries
help Print this help
Options:
-h, --help output usage information
-V, --version output the version number