The utility model provides an automatic changeover switch electric appliance sampling circuit comprising 24 resistors R1-R24 and 6 capacitors C1-C6. Input power supplies V1, V2 and V3 are A-phase, B-phase and C-phase power supplies of a main power supply, and power supplies V4, V5 and V6 are A-phase, B-phase and C-phase power supplies of a standby power supply. The beneficial effects of the automatic changeover switch electric appliance sampling circuit are that the used core devices adopt integrated chips so that reliability of the whole system is enhanced; peripheral devices are mainly composed of the resistors and the capacitors so that complexity level is relatively low and product processability is enhanced; six paths of AC signals can be completely processed within 37ms and effective values of the six paths of AC signals can be calculated so that efficiency is higher than that of a common single-chip microcomputer system; the automatic changeover switch electric appliance sampling circuit has a pure hardware sampling system without software programming so that use difficulty is reduced; frequency and phase difference measurement is realized so that the automatic changeover switch electric appliance sampling circuit can be developed into a power generation and grid-connected system; harmonic wave analysis can be performed and the automatic changeover switch electric appliance sampling circuit can normally work in a complex electromagnetic environment; and the automatic changeover switch electric appliance sampling circuit can directly withstand meter shaking insulation measurement in an insulation and voltage withstand test experiment.