The invention provides an independent full-automatic concurrent single-point modification method. The independent full-automatic concurrent single-point modification method comprises the following steps: when an ammeter receives a stable voltage and current signal, the ammeter judges whether the voltage and current signal is within the effective range of the rated voltage and rated current of the ammeter; if voltage and current values are not within the effective range, the voltage and current values are invalid, and the voltage and current signal returns; if the voltage and current values are within the effective range, floating-point arithmetic is used for calculation and correction on angular difference and ratio errors of three-phase voltages and currents. According to the independent full-automatic concurrent single-point modification method, the autonomous meter regulation technology is adopted, it is unnecessary that gain is calculated by a background computer and then written back into the ammeter, and the ammeter calculates and saves the gain autonomously instead. In this way, the independent full-automatic concurrent single-point modification method has the advantages that time for communication between the ammeter and the background computer is saved, the method is not limited by the number of ammeters, and the larger the number of regulated ammeters is, the more efficiency is improved.