@xuelainiao That is tricky, as each individual NodeBB will have separate user databases. You may want to consider adapting the session-sharing plugin so that a cookie is saved on login and read from other the NodeBBs.
I'm not sure if I understand your question exactly, but you can write a plugin to listen to a new route (URL endpoint) or interprocess communication and load and call NodeBB libraries.
You may consider using this plugin Git repo as a bootstrap to get you started quickly. Remember that the plugin.json, package.json, and library.js are the first files to work with. The plugin repo name / directory name will need to match the glob nodebb-plugin-* and it needs to be directly under the node_modules/ directory which is at the root of your NodeBB directory.