Path planning is an important part of the objective of UAV task.Considering that the Particle Swarm Optimization (PSO) algorithm is fast in convergence in the early stage and easy to fall into local optimum in the later stage, an improved PSO combined with the Beetle Antennae Search algorithm is proposed, which is applied to three-dimensional path planning of UAVs.In the improved PSO algorithm, by using the advantage of the individual beetle, which has its own judgment on the environment space in each iteration, the path is more reasonable and the search efficiency is higher.The simulation results show that: Compared with PSO, the three-dimensional path planning of UAV based on improved PSO is more effective with less cost.