The present invention discloses a simulated low-voltage power supply system which includes: purify power supply used for dividing rectified and stabilized voltage into two roads to output to AC/DC power supply and a sampling circuit; AC/DC power supply converts input AC power supply into DC and outputs to a inverter circuit; the sampling circuit is used for sampling phase, frequency and pressure to one road of AC power supply output and outputting sampled electrical level signal to a phase locked loop circuit; the phase locked loop circuit is used for generating wave shape of same phase and frequency with the sampling circuit; the output control circuit is sued for outputting voltage waveform generated by the phase locked loop circuit to the inverter circuit; the inverter circuit is used for converting converted DC power supply to the other road of AC power supply of same phase, frequency and pressure according to voltage waveform of the output control circuit; a isolation wave filtercircuit is used for further filtering harmonic of AC power supply generated by the inverter circuit and outputting as the other road of communication isolation power supply after carrier isolated.