The invention provides a PCB slot locking device, which comprises a central shaft, a front wedge block, a rear wedge block, a locking wedge block, a locking screw, a locating pin, a flat washer and anelastic washer; the locking device comprises a central shaft, a front wedge block, a rear wedge block, a locking wedge block, a locking screw, a locating pin, a flat washer and an elastic washer. Themiddle shaft is sleeved in the groove of the front wedge, the rear wedge and the locking wedge, the locking wedge is located in the middle of the middle shaft, and the front wedge and the rear wedgeare respectively located at the two ends of the locking wedge and the contact surfaces of the two wedge which are in contact with each other are in contact with each other. The front wedge and the central shaft are fixed by a locking screw, the rear wedge and the central shaft are fixed by a locating pin, and the locking wedge can slide relative to the central shaft. The front wedge and the central shaft are fixed by a locking screw, and the rear wedge and the central shaft are fixed by a locating pin. The locking device has the advantages of simple structure, convenient loading and unloading,and solves the technical problems of locking failure caused by loosening the locking screw caused by the vibration of the chassis or dropping the front wedge block into the chassis caused by misoperation when replacing the PCB card. Therefore, the PCB slot locking device of the invention is suitable for general promotion and application.