Nowadays, more importance has been attached to the energy consumption of household energy storage inverters. This paper proposes a design scheme of original-auxiliary dual power supply for household energy storage inverters, so that the inverter uses a large-capacity power supply when it is loaded with medium or large loads, and uses a small-capacity power supply when it is loaded with light loads or no load, and avoids large losses caused by the two-stage inverter when using a large-capacity power supply with a small load with the purpose of energy saving. The solution adopts a peak detection circuit on the AC power supply side, which can accurately detect the tiny current when the 1∼3W-load is connected, so as to accurately judge the access and exit of the load, so that the power supply can enter or exit the power saving mode of the small-capacity power supply in a timely and flexible manner. In this paper, the feasibility and rationality of the scheme are tested by simulation, and it is proved that the power saving effect of the scheme is remarkable.