The invention provides a backflow cable anti-theft device capable of automatic alarm. The device comprises anti-theft screws and anti-theft fixing clips for fixing backflow cables, a plurality of theanti-theft screws and the anti-theft fixing clips are arranged at intervals, the device also includes a vibration sensor, a data collector and an alarm fixedly connected to the anti-theft screws and the anti-theft fixing clips, the vibration sensor collects vibration signals of the backflow cables and/or the anti-theft screws and/or the anti-theft clips, the vibration sensor is arranged at the cooperation of the anti-theft screws or the anti-theft clips and the backflow cables, the data collector acquires the vibration signals collected by the vibration sensor and transmits the vibration signals to the alarm, the alarm includes an acquisition unit and a processing unit, an acquisition unit acquires the vibration signals transmitted by the data collector, and a processing unit determines whether or not the backflow cables are stolen according to the vibration signals acquired by the acquisition unit, and issues an alarm according to a judgment result, thereby achieving the automatic alarm when the backflow cables are stolen, so that staff stops the backflow cables from being stolen in time.