In this paper,the design problem of intelligent ship autopilot with input saturation,unmeasured yaw rate and prescribed performance is investigated.An adaptive fuzzy output feedback controller is proposed based on state observer,auxiliary system and error transformation system.The fuzzy logic system (FLS) is employed to estimate the unknown nonlinear function,a state observer is designed to estimate the unmeasured yaw rate,an auxiliary signal for input saturation is established to compensate the mismatch between the controller signal and the actuator signal,and an error transformation system is also established to handle the ship heading tracking error.According to Lyapunov theory,the closed-loop system is proved to be bounded for all signals.Finally,simulation results are given to verify the effectiveness of the proposed scheme.