Abstract: To further study the quantization process of state signals in ship course keeping control system, a new controller with adaptive sliding mode gain is designed and a feedback control method of ship course keeping based on high gain adaptive observer is proposed. The input and output quantization process of the system signal is described through constructing a second-order nonlinear motion analysis model. A quantized adaptive sliding mode controller was designed based on a high gain observer and logarithmic quantizer。At the same time, the fan-shaped constraint method is combined to eliminate the impact of quantization errors on the system. A logarithmic quantizer is used to quantify the state variables and input variables in the designed control system, and the quantized state feedback information is applied to the design of the ship heading maintenance controller. The results analysis verified the effectiveness of the designed observer in evaluating the relevant parameters of the ship's heading and bow turning angular velocity. Not only the course control error approaches zero infinitely, but also the observation error converges to the origin. Based on Matlab Simulink simulation analysis and Lyapunov stability theory, the designed controller has been proved with excellent heading tracking performance and the stability of the closed-loop control system at the same time. The research provide a meaningful application reference value for the study of ship heading maintenance control and the practical significance of the project is far-reaching.