The utility model discloses an accurate power failure calibrator for a low-voltage power distribution area. The system comprises a host which is provided with a current transformer, a clock and a GPRSmodule, detects the current value of a branch line switch at a low-voltage busbar of a power distribution room through the current transformer, determines the time for collecting the current value through the clock, and transmits the three-phase current value of the branch line switch at the whole second moment and the corresponding time to a hand-held terminal through the GPRS module; the slavemachine is provided with a current transformer, a clock and a GPRS (General Packet Radio Service) module, detects the three-phase current value of the power supply side of the incoming line switch atthe building head box through the current transformer, determines the time for collecting the current value through the clock, and sends the three-phase current value of the incoming line switch at the whole second moment and the corresponding time to the handheld terminal through the GPRS module; the hand-held terminal is provided with a clock, a GPRS module and a display screen, the clocks of the host, the slave and the hand-held terminal are synchronous, the GPRS module is communicated with the host and the slave, and the display screen displays current values and acquisition time acquiredby the host and the slave in real time. The calibration device is convenient to operate and can realize accurate calibration.