The invention discloses a device and a method for accurately adjusting a bottom dead centre of a press. The device comprises an eccentric shaft and a servo motor which is in transmission connection with the eccentric shaft, wherein the eccentric shaft is hinged with a sliding block of the press and a connecting rod of the press; and a worm and worm gear reduction mechanism is arranged between the eccentric shaft and the servo motor. The method comprises the following steps of: acquiring the accurate positions of different bottom dead centres when the eccentric shaft is positioned in different angles; or acquiring accurate adjustment quantity and compensation quantity by means of an accurate angular displacement and control system of the servo motor according to automatic detection and signal processing results; and locking the corner positions of the eccentric shaft through the worm and worm gear reduction mechanism by the servo motor. By the invention, the processing quality of a product is improved, rejection rate is reduced, and the adjustment method is simplified by accurate pre-adjustment and automatic accurate compensation on the positions of the bottom dead centres of the sliding block.