A lift safeguard comprises a relay and an alarm device, and the relay comprises a relay coil and relay contacts. The relay contacts, the alarm device and contacts of a car door lock contactor of a lift are connected in series to form a first link. The relay coil and contacts of a hall door lock contactor of the lift are connected in series to form a second link, and the second link is connected in parallel with the first link. When a hall door is abnormally opened, the contacts of the car door lock contactor of the lift in the first link are closed, the contacts of the hall door lock contactor of the lift in the second link are closed, the relay coil of the relay is electrified to drive the relay contacts in the first link to close, as a result, the circuit of the first link is connected, and the alarm device is started. Consequently, when the hall door is abnormally opened, the lift safeguard can warn related personnel of the abnormal state of the lift, thus preventing the accident from further escalating.