Abstract: Aimed at the unmanned surface vessel path planning problem， in the report， in order to solve the low efficiency problem， the low convergence speed problem， and the deadlock problem at the early stage of traditional ant colony algorithm， the initial pheromone uneven distribution， introducing weighting factor， improving ant colony information update rules， punishing the pheromone of the last two steps， were used to improve the initial method. The simulation results of the comparative tests indicated that the improved method achieves good results.