ObjectiveThis paper aims to explore the influence of rudder-fin combined structure on the induced noise. Methods To this end, the flow field and sound field of a rudder are calculated using the two-way fluid-structure interaction theory, and the sound vibration laws caused by the change of the rudder blade material and rudder stock position are studied.ResultsThe results show that, among the three materials of aluminum alloy, titanium alloy and steel, the fluctuation of the fluctuating pressure caused by the steel rudder is the smallest, and the first peak point of the steel rudder appears last; the first-order peak frequency and amplitude increase with the backward movement of the rudder stock position, while the second-order frequency decreases with the backward movement of the rudder stock position; the forward movement of the rudder stock will reduce the total sound pressure level within 100 Hz. ConclusionsFurther analysis indicates that, the sound vibration characteristics of the steel rudder are the best among the three materials, and the forward movement of the rudder stock position can improve the sound vibration characteristics of the rudder-fin structure within a certain range. This study has certain guiding significance for the acoustic design of submarine rudder structures in order to improve the acoustic stealth performance of submarines to a certain extent.