Abstract： The propeller wake is calculated by a surface panel method, and then the attack angle of the twisted rudder can be designed through the propeller wake. An approach of anticavitation twisted rudder is proposed. The hydrodynamic performance of rudder after propeller is calculated by a computational fluid dynamics (CFD) method, and it is validated by the rudder force tests. The pressure distributions of the twisted and ordinary rudders are compared with each other. The peak of negative pressure on the twisted rudder is smaller than that of the ordinary rudder. The twisted rudder has a better anticavitation performance and can reduce cavitation erosion，vibration and noise. Because the twisted rudder has better match performance for the propeller wake than the ordinary rudder, it has  lower cross force and torque than the ordinary rudder when the rudder angle is zero. The fact is favorable to rudder and steering engine.