The invention discloses a method for rapidly detecting high-error electric power in a single phase. The method is characterized by comprising a connecting step, an inputting step, a locking step, and a determining step. The method measures a single-phase electric meter by using a device for rapidly detecting high-error electric power in a single phase adopting voltage locking technology, may input reference voltage signal data into a detection device by manual input or one-time pre-measurement, detects the electric meter to be detected through the data, does not require real-time voltage values in calculation, retains an original calibration function, simplifies a wiring way in order to achieve rapid measurement, and greatly improves work efficiency. For the electric meters in the same line, the detection may increase efficiency by 50%. Voltage line are not required to be connected, which means that an exposed part of a power supply is not contacted and a safety level is greatly increased.