This paper details the implementation of a robust PID fin control system designed by using close-loop gain shaping algorithm (CGSA) to stabilize the roll motion of a training ship “YUKUN”. Firstly, the effect of different representation of linear and nonlinear damping and restoring moment on the roll response is investigated. The solutions of different roll response equations are solved with the fourth order Runge-Kutta method. In the following, the design process of robust PID controller using CGSA is described and the controller designed has concise structure and strong robustness. The typical cases of ship operations are worked out and a roll reduction of 80%-85% is achieved in various simulation conditions.