The unmanned surface vessel equipped with a dipping sonar can be used as the supplement for manned surface ships in the anti-submarine warfare. The combat scenario is firstly put forward for the unmanned surface vessel which cooperated with manned surface ships based on the dipping sonar. Then it is designed of the fan-shaped submarine searching strategy model for the unmanned surface vessel. Considering the different circumvention situations of submarines, such as maintaining heading and speed, changing heading with constant speed, changing speed in the same heading, and changing heading and speed simultaneously, the simulation experiments of searching submarine are carried out for the unmanned surface vessel. The simulation results show that the unmanned surface vessel can effectively detect the submarines by fan-shaped searching strategy.