Reactive power metering circuit in existing power metering chips cannot meet the requirements of high metering accuracy and low hardware overhead at the same time. In order to solve this problem, a new method of reactive power metering is proposed, which uses three firstorder IIR filters, in which the phase shift filter in the voltage channel makes the voltage signal shift -90 degrees phase. The two amplitude compensation filters in the voltage channel and the current channel jointly compensate for the attenuation of the signal amplitude generated by the phase shift filter. The two amplitude compensation filters are required to be designed to have the same structure and parameters, thus their application in parallel mode will not change the phase difference between voltage and current. The design method of efficient reactive power metering system is proposed, especially the optimization method of amplitude compensation filter design. The simulation and actual product test results show that the reactive power metering method not only consumes less hardware resources, but also achieves high metering accuracy, which is better than the reactive power metering methods of the existing power metering chip.