Aiming at the problem of large load fluctuation range in existing control methods for marine controllable pitch propellers，an automatic control method for marine controllable pitch propellers based on genetic algorithm is proposed. Firstly， a PID controller is designed. Secondly，the genetic algorithm is applied to optimize PID parameters to determine the optimalcombination of pitch angle and rotational speed under different working conditions，so as to ensure that the marine controllable pitch propeller operates efficiently at all times. Test results show that after the application of the proposed method，the root bending moments of blade 1 to blade 4 are all kept below 3 000 kN·m，and the load fluctuation amplitudes at the blade roots ofthe marine controllable pitch propeller meet the expected requirements. The additional loads of the foundation structure near thestern post are all kept within the allowable range，which effectively improves the operational stability and reliability of ships in complex navigation environments.