An on-board charging apparatus is provided to implement high-power charging. The on-board charging apparatus includes an alternating current (AC) to direct current (DC) conversion circuit (AC/DC conversion circuit), a power factor correction (PFC) circuit, and a DC/DC conversion circuit. An alternating current terminal of the AC/DC conversion circuit is connected to an alternating current terminal of the PFC circuit. The AC/DC conversion circuit is configured to: receive a first alternating current voltage at the alternating current terminal of the AC/DC conversion circuit, and convert a first component of the first alternating current voltage into a first direct current voltage. The PFC circuit is configured to: convert a second component of the first alternating current voltage into a second direct current voltage. The DC/DC conversion circuit is configured to: convert the first direct current voltage and the second direct current voltage into a third direct current voltage.