In view of the path planning of the unmanned AUV (autonomous underwater vehicle) in the complex sea battlefield environment, the environment model is complex and there are many constraints. A relatively perfect sea battlefield environment model including battlefield shape, enemy threats, obstacles, and sea current field was established. The AUV navigation time and threat time were the shortest as the optimization goal, and an oscillation-based type was given. The AUV global path planning method of the oscillation IWO(invasive weeds optimization) algorithm was compared with other three path planning algorithms, such as the standard IWO algorithm, the full-oscillation IWO algorithm and the PSO (particle swarm optimization) algorithm respectively. Simulation results show that the proposed method which has strong searching ability and excellent robustness, can effectively plan the navigation path which meets the performance requirements for the AUV in the complex sea battlefield environment.