As the core technology of Multiple unmanned aerial vehicle(UAVs), multi-aircraft cooperative track planning is an effective means to improve the combat efficiency of UAVS. A multi-UAV cooperative track planning method based on improved RRT algorithm is proposed in this paper. Firstly, the goal-biased strategy is added to optimize the selection of sampling points, and the gravitational potential field is incorporated to improve the generation of new node x_new, so that the gravitational direction of the target point to the nearest node is used as the growth direction of the random tree to accelerate the convergence speed of the algorithm. The objective function of multi-UAV cooperation is established considering the constraints of multi-UAV cooperation. The method of sudden threat replanting is also given. The simulation results show that the improved RRT algorithm can be planned for optimal cooperative tracks under the condition of satisfying the cooperative constraints.