Unmanned surface vehicles (USVs) have been applied in various areas nowadays. With respect to the uncertain disturbance rejection and accurate trajectory tracking issues, a modified fixed-time terminal sliding mode controller (FiTSMC) is provided for USVs in this paper. There are two primary improvements involved in the proposed controller. Firstly, a superior time scaling function is introduced to avoid excessive tracking errors causing the input saturation. Secondly, in virtue of combining the FiTSMC with extended state observer (ESO), a combined controller termed ES0-FiTSMC is proposed to maintain the convergence time and tackle with challenge resulting from the uncertain disturbances and model parameters. The simulation results illustrate the feasibility of accurate trajectory tracking in the uncertain environment.