The invention discloses an anti-theft safety device applied to an electric power field and a locking device. The anti-theft safety device comprises a door frame, an anti-theft door, a PLC, a wireless alarm, a lower clamping groove, the locking device, a protection device, a connecting layer, an outer layer, a coded operation panel, an upper clamping groove, a sound-light alarm lamp, a first cable, a touch switch, a shell, a second cable, a storage battery and an electromagnetic lock. The anti-theft safety device applied to the electric power field and the locking device are reasonable and simple in structure, low in production cost, and convenient to mount; the protection device is similar to a normally-closed switch mounted on the surface of the anti-theft door, the cables can be destroyed when the lock and the door are destroyed by lawbreakers, an open circuit is formed through the protection device, a door destroying signal is sent to the PLC, then the PLC gives out an alarm through the wireless alarm and the sound-light alarm lamp, the wireless alarm directly transmits the destroying signal to a scheduling duty system to send alarm information, and the sound-light alarm lamp can directly overawe the lawbreakers.