The invention discloses a noise suppression method for a marine asynchronous motor system. The method comprises the following steps: connecting a capacitor middle point of the asynchronous motor system and a middle point of a motor three-phase winding, calculating electromagnetic torque ripples of a three-phase motor at different loads and rotating speeds, and drawing q curves; calculating a theoretical value of the electromagnetic torque ripple at current rotating speed and load when online closed-loop control is carried out on the motor, comparing the theoretical value with an actual value of the electromagnetic torque ripple of the current motor, and comparing and outputting a voltage compensation value through a PI adjuster; and compensating the voltage compensation value to a voltage value output by V/F, synthesizing output voltage value and an integrated angle of the V/F into an output voltage vector, transmitting the voltage vector to a PWM module and outputting a drive signal by the PWM module. The method can test the value of the electromagnetic torque ripple of the motor in an off-line manner and carry out closed-loop control by the value of the electromagnetic torque ripple of the motor and the value of the electromagnetic torque ripple of an online system, so that the value of the magnetic field ripple of the motor is improved and the electromagnetic noise problem of the motor is solved.