The invention relates to a backflow cable antitheft alarm system and a control method. The backflow cable antitheft alarm system comprises a monitoring host, a monitoring alarm module, a server and a power supply module; the monitoring host comprises a single-chip microcomputer, an RFID radio frequency communication module and a GPRS wireless communication module; the RFID radio frequency communication module and the GPRS wireless communication module are connected to the single-chip microcomputer; the monitoring alarm module comprises an alarm device and a vibration sensor; the alarm device and the vibration sensor are in wireless connection with the monitoring host through the RFID radio frequency communication module; the server is in wireless connection with the monitoring host through the GPRS wireless communication module; and the power supply module is connected to the monitoring alarm module. The invention is advantageous in that the on-site pavement of transmission lines is unnecessary, the communication distance is long, the cost is saved, the installation is simple, faults are not easy to happen, the maintenance is easy, and the vibration sensor is not high in requirement for installation. The backflow cable antitheft alarm system is not affected by the environment, and has the alarm device and realizes the on-site alarming.