When installing cnpm source, there are these error problems. How can this be solved?

  node.js, question

When installing cnpm source, there are these error problems. How can this be solved?

npm ERR!  Darwin 15.6.0
 npm ERR!  argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "cnpm" "--registry=https://registry.npm.taobao.org"
 npm ERR!  node v6.8.0
 npm ERR!  npm  v3.10.8
 npm ERR!  path /usr/local/lib/node_modules
 npm ERR!  code EACCES
 npm ERR!  errno -13
 npm ERR!  syscall access
 
 npm ERR!  Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
 npm ERR!  at Error (native)
 npm ERR!  { Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
 npm ERR!  at Error (native)
 npm ERR!  errno: -13,
 npm ERR!  code: 'EACCES',
 npm ERR!  syscall: 'access',
 npm ERR!  path: '/usr/local/lib/node_modules' }
 npm ERR!
 npm ERR!  Please try running this command again as root/Administrator.
 
 npm ERR!  Please include the following file with any support request:
 npm ERR!  /Users/wscart/npm-debug.log

Insufficient permissions (‘permission denied’),sudo npm install -g xxx