This paper addresses the dynamic memory event-triggered dynamic positioning control issue of a nonlinear mass-switched unmanned marine vehicle under denial-of-service attacks. Initially, a switched fuzzy model is designed to describe the nonlinear mass-switched unmanned marine vehicle. Both the nonlinear characteristics of the vessel and mass-switched behavior are considered in this model. Then, a dynamic event-triggered mechanism with a memory element is proposed. The historical information of dynamic variables is used to adjust the triggering threshold, further conserving limited communication resources. Based on this mechanism, a controller is designed to compensate for ocean disturbances. Furthermore, by employing the multiple Lyapunov function approach, a solvable criteria for the dynamic memory event-triggered dynamic positioning control issue of a mass-switched unmanned marine vehicle system under denial-of-service attacks is provided. Under denial-of-service attacks, the proposed control scheme can handle communication interruptions caused by network attacks, ensuring that the mass-switched unmanned marine vehicle maintains dynamic positioning performance under adverse network conditions. Finally, the effectiveness of this control scheme is validated by a case study involving a mass-switched vessel.