Objectives In order to solve the problem that unmanned boats cannot carry out reasonable and effective autonomous obstacle avoidance under dense obstacle sea conditions. Methods An improved dual-window dynamic window approach(DWA)obstacle avoidance algorithm based on fuzzy control strategy is proposed, that is, a sensing window based on the onboard sensor is designed on the basis of the conventional speed window, and the dual-window model composed of the speed window and the sensing window is further optimized The speed space is constrained, and the weight of the evaluation function is dynamically adjusted based on the fuzzy control strategy based on the obstacle distribution state and the distance between the UAV and the obstacle. Results The simulation experiment results show that, compared with the original DWA algorithm, the path planned by the improved algorithm under unknown dense obstacle sea conditions is more reasonable and smoother, which not only solves the problem of unmanned boats detouring outside the dense obstacle group, but also takes into account The safety of obstacle avoidance navigation is improved, the number of iterations and running time can be shortened by more than 20%. Conclusions The research results have certain reference value for the research on autonomous obstacle avoidance technology of unmanned boats.