Abstract: Fuzzy control is an effective method to solve the unmanned surface vehicle（USV）heading control problem. Still，its fixed fuzzy rules and universe often fail to meet the high precision requirements of the control system. In this regard，we proposed a USV heading fuzzy control strategy based on the variable universe. Firstly， a nonlinear mathematical model of the USV was established，and a nonlinear controller was designed. Then，according to the conventional fuzzy control theory，the universe was adjusted using the stretching factor. We determined the stretching factor by combining the function and fuzzy control ideas to improve the applicability of fuzzy rules and achieve the adaptive effect. Finally，the heading tracking effect of three control strategies：conventional control，fuzzy control，and variable universe fuzzy control，was compared and analyzed under the two cases of no environmental disturbance and environmental disturbance，respectively. The experimental results showed that applying the variable universe fuzzy control strategy to the heading control of USV could achieve good results and improve the system's control accuracy and self-adaptive capability.

Key words: unmanned surface vehicle, heading control, variable universe, stretching factor, fuzzy control