The invention discloses a vehicle-mounted multiplex charging machine. The vehicle-mounted multiplex charging machine comprises a high-voltage battery, three inductors L1, L2 and L3, and three IGBT bridge arms in parallel connection mutually. A positive pole of the high-voltage battery is connected with one ends of the inductors L1, L2 and L3 through relay switches S1, S2 and S3. The other ends ofthe inductors L1, L2 and L3 are connected with middle nodes of the three IGBT bridge arms correspondingly. A negative pole of the high-voltage battery is directly connected with a jointly-connecting end of the three IGBT bridge arms. The connecting ends of the relay switches S1 and S2 and the inductors L1 and L2 are a live line connector and a zero line connector of a power grid correspondingly. The two ends of the three IGBT bridge arms in parallel connection mutually are connected with an inverter-motor system. IGBT devices constituting the three IGBT bridge arms are connected and controlledthrough a controller module. When the vehicle-mounted multiplex charging machine works, a Boost working state, a state of single-phase power grid connection to charge the battery, a single-phase grid-connected inversion state, and a vehicle-vehicle mutually-charging state are included. The vehicle-mounted multiplex charging machine adopts different relay switch combinations, equipment can work indifferent states, and different functions are achieved.