This paper proposes a novel trajectory tracking control strategy for autonomous surface vehicles (ASVs), subject to actuator constraints and under denial-of-service (DoS) attacks. Firstly, a fixed-time disturbance observer (FTDO) is used to estimate and compensate unknown external disturbances, which enhances the robustness of the motion system. Secondly, a novel fixed-time filter is designed by combining dynamic surface technology with fixed-time control, which avoids the problem of differential explosion, and reduces the filtering error. Lastly, in order to address the effects of actuator constraints and DoS attacks, an auxiliary system (AS) and a compensation system (CS) are included in the fixed-time dynamic surface controller based on FTDO. The proposed method improves the robustness, stability and accuracy of the closed-loop system. Additionally, the reference tracking error converges to the neighborhood of the origin within a fixed-time. The superiority of the proposed control method over traditional control strategies from the existing literature is demonstrated in simulations.