The invention discloses a charging system compatible with AC and DC input, which comprises a detection module, a control module and a charging module, wherein the detection module is used for detecting the type of an input power supply; the control module is connected with the detection module for adopting a three-phase control algorithm to control and process the input power supply when the input power supply is detected to be a three-phase AC power supply, and carrying out DC control processing on the input power supply when the input power supply is detected to be a DC power supply; and the charging module is connected with the control module for outputting the power after being processed to an electric vehicle and charging the electric vehicle. Correspondingly, the invention also discloses a charging method compatible with AC and DC input. The system of the invention can be compatible with two voltage sources of AC and DC, the cost is reduced, the size is reduced, and the system reliability is improved.