Abstract: For multiple unmanned surface vehicles (USVs) with unknown positions and limited communication bandwidth under GPS-denied environments, an event-triggered cooperative target encircling method based on relative distance measurements is proposed. First, a target encircling controller is designed for an USV using the estimation of distance change rate, where only the distance information between the USV and the target is utilized, achieving specified-distance encircling. Then, a distributed cooperative controller based on phase angle prediction is developed, which adjusts the vehicles’ velocities through phase deviation estimation, achieving uniform distribution along the encircling path. Moreover, a cooperative communication strategy with a dynamic event-triggered mechanism is designed to effectively reduce the transmission frequency of phase angle estimation signals among the vehicles. System stability is proven using the Lyapunov function, and Zeno behavior is excluded. Finally, simulation results demonstrate that multiple USVs can achieve uniform target encircling, and the event-triggered mechanism reduces communication frequency by approximately 80%.