A return spring adjustment apparatus and method of a wave power system. The apparatus comprises return springs (5, 9), a stepper motor (6), transducers (7, 10, 27, 29), a single chip microcomputer control module (8) and a power source. The two ends of the return springs (5, 9), a chassis (12) of the stepper motor, a rotor (11), the two ends of the transducers (7, 10, 27, 29) can all be randomly arranged in series, and connected with a spindle (4) and a frame (22). When a single chip microcomputer detects that the transducers (7, 10, 27, 29) measure that the pulling force is too large or too small, it sends an instruction to the stepper motor (6) to perform adjustment. After the adjustment is completed, the stepper motor (6) stalls and brakes, so that the return springs (5, 9) can work in within a specified range.