Compared with single robot, multi-robot system has the characteristics of higher working efficiency and better flexibility, which has received increasing attention. Trajectory planning determines the operating efficiency and motion performance of its end effector. The multirobot system has a large amount of calculation for the coordinated trajectory planning of each robot in the case of largescale overlapping of workspaces. Various methods of multirobot trajectory planning were analyzed and summarized in detail from the aspects of basic trajectory planning, optimal trajectory planning and deep learning, and the technology development trend in this field was analyzed and prospected which indicated the research direction of future work.