The invention discloses a vibrating screen natural frequency regulating method and device; the method comprises the steps that the free vibration in a vertical direction of a vibrating screen on which a natural frequency regulating device is preinstalled is actually measured and analyzed to obtain the actually measured natural frequency; calculated natural frequency and a corresponding regular vibration mode are calculated through a general mathematical model; the actually measured natural frequency is compared with design natural frequency, and whether the natural frequency needs to be adjusted or not is judged according to the error criteria of the natural frequency. If adjustment is needed, an adjustment target value is determined and regulation is carried out through the regulating device, so as to judge whether to repeat the steps to the actually measured natural frequency after adjustment according to the error criteria. The device comprises a dovetail groove guide rail and a slider, a slider steel wire rope and a connector, a double-lug spring base and a pressure plate, a force adjusting bolt pair, a suspension compression spiral spring, a pressure plate steel wire rope, a connector and a three-lug suspension. The device has the characteristics of good economy, simplicity in operation, and assistance in absorbing the shock of a screen body and reducing the swinging and torsion of the screen body.