Disclosed is a power supply system, including: a high-voltage input power distribution cabinet, a high-low voltage conversion cabinet, and a low-voltage output and control cabinet, the high-low voltage conversion cabinet is provided with at least one high-voltage chamber provided with a high-voltage bus bar, at least one low-voltage chamber provided with a low-voltage bus bar, an insulating partition between the high-voltage chamber and the low-voltage chamber and a plurality of power supply modules; each of the power supply modules bridges the high-voltage and low-voltage chambers and includes a high-voltage cavity, a low-voltage cavity and an isolation unit, connecting terminals of the high-voltage and low-voltage cavities are respectively disposed corresponding to the high-voltage and low-voltage chambers and electrically connected to the high-voltage and low-voltage bus bars respectively, and the isolation unit is connected to one end of the high-voltage cavity and one end of the low-voltage cavity.