A charging circuit for a vehicle charger includes a front high-voltage protective circuit, a rear high-voltage protective circuit, a first filtering circuit, an over-voltage protective circuit, a high frequency step-down switching regulator, a second filtering circuit, a frequency modulation circuit, a reference voltage input circuit, a sampling circuit, a short-circuit protective circuit and two charging interfaces. The front high-voltage protective circuit connects to a vehicle DC power, the first filtering circuit connects the front high-voltage protective circuit to the switching regulator, the second filtering circuit connects to an output point of the switching regulator to the rear high-voltage protection circuit, the frequency modulation circuit connects to a second input point of the switching regulator, the third input point of the switching regulator connects to the reference voltage input circuit, the short-circuit protective circuit connects the second filtering circuit to the fourth input point of the switching regulator, the sampling circuit connects the second filtering circuit to the fifth input point of the switching regulator, the rear high-voltage protection circuit connects to the two charging interfaces. For the unique design, the charging circuit for a vehicle charger has a short-circuit protective function and provides two charging interfaces.