The invention discloses a low-voltage single-phase power supply system of 10 kV transformer and 220 V, which comprises 10 kV-220 V three-phase-to-two-phase transformer, an electric energy collection unit, an unbalance control unit, a reactive power control unit and an AC-DC-AC module connected in sequence At first, that three-phase voltage is convert into two-phase voltages by use a transformer, the electric quantity is collected by connected with an electric energy acquisition unit, and the collected electric quantity is sent to an unbalanced control unit and a reactive power control unit, the unbalanced control unit is used for monitoring the current unbalance degree between the alpha phase and the beta phase, and the AC-DC-AC module regulates the two-phase current, and the reactive power control unit is used to monitor the power, the AC-DC-AC module regulates the power in the circuit; Compared with the power supply mode of the two-inlet single-phase transformer, the power supply system provided by the invention can solve the three-phase unbalance problem of the 10kV side, greatly reduce the probability of the three-phase current unbalance of the 220V side, reduce the capacity ofthe three-phase unbalance treatment device, reduce the line loss, and improve the power supply quality.