Multi UCAV Cooperative Path Planning is an important part of multi UCAV cooperative combat, and the results of collaborative operations have many guiding roles. Multi UCAV cooperative path planning belongs to multi peak function optimization problem, and the solution stability is relatively poor. In order to solve this problem, first, on the basis of analysis under condition of multi Aircraft Cooperative limitations, and combined with the core index of single track planning, the paper builds up multi UCAV cooperative route optimization function. Then, the paper utilizes the characteristics of stability of multi swarm algorithm with the gray wolf Lee(MP-GWO) in solving multi peak optimization problems on the function to solve it. Finally, the paper compares the MP-GWO with the GWO algorithm, EA algorithm and solution in the new threat environment superior to verify the feasibility of the algorithm. The simulation results show that the MP-GWO algorithm has the stability of the multi peak problem in solving environment, and adapts to unexpected threat circumstances.