Ships may be disturbed by various factors such as wind, waves, currents and shore wall effects in automatic berthing. Therefore, we design a ship automatic berthing controller based on event-triggered mechanism and model predictive control to solve the automatic berthing problem of fully actuated ships under the influence of model uncertainty, actuator saturation, unknown environmental disturbance and shore wall effect. Firstly, a three-degree-of-freedom model of the fully actuated ship is linearized and discretized, and out-of-berth stabilizing followed by parallel berthing is adopted according to the characteristics of the fully actuated ship. Then, an event-based adaptive horizon model predictive control scheme is proposed to improve the computational speed, and the proof of stability is also proven. Finally, simulation experiments are conducted on a fully actuated ship to compare the proposed control scheme with other known methods, and the experimental results show that the proposed control scheme not only significantly reduces the calculation time, but also has better control performance.