As a new carbon nanomaterial with wide applications, nitrogen-doped graphene exhibits excellent electrical conductivity and electrochemical properties. Recently, researchers have achieved fruitful results by choosing appropriate doping methods and precisely controlling the nitrogen doping content and configuration. We reviewed direct synthesis methods and post-synthesis methods，which have obtained different microstructures and performances. Herein, we have discussed the merit and demerit of different preparation methods and the technological limitation to the scalable preparation of high-performance nitrogen-doped graphene. We hope to provide a reference for a scalable, simple, feasible and environmentally friendly nitrogen-doped graphene preparation technology.