Abstract: In the process of multi-UAV coordinated operation, mission planning is crucial for UAV, and exists throughout the operation of UAV. The paper summarizes the system architecture, control mode and the research status of key technologies in the multi-UAV task planning systems. This paper elaborates the model and algorithm of target assignment, path planning and trajectory correction, analyzes the characteristics and applicability of the algorithm, and illustrates the improvement of some algorithms by researchers. Finally, the future development trend of multi-UAV mission planning technology and our next work direction are put forward.