The invention discloses a metering circuit, and the metering circuit comprises a metering module connected with a power frequency power supply. The metering module comprises a metering chip, a current sampling circuit, a voltage sampling circuit, and a pulse generation loop. The current sampling circuit and the voltage sampling circuit are connected with the power frequency power supply and the metering chip. The current sampling circuit collects a voltage signal of the power frequency power supply, and transmits the voltage signal to the metering chip. The voltage sampling circuit collects a current signal of the power frequency power supply, and transmits the current signal to the metering chip. The metering chip is connected with the pulse generation loop, converts the received voltage signal and current signal into pulses and transmits the pulses to the outside through the pulse generation loop. The metering chip carries out the monitoring of the current and voltage signals of the power frequency power supply, directly converts the signals into pulses through the metering module, transmits the pulses to a microcontroller, completes the following metering operation through the microcontroller, enables the circuit structure to be simple, and enables the function to be complete.