A train power supply circuit comprises a first train power supply cabinet (1) and a carriage power supply circuit (2). The first train power supply cabinet (1) comprises a first power source (11) and a first output port (12) both connected by a first contactor (KM1), a second power source (13) and a second output port (14) both connected by a second contactor (KM2), and a third contactor (KM3) connected to the first contactor (KM1) and the second contactor (KM2). The carriage power supply circuit (2) comprises a first loop (21) connected to the first output port (12) and a second loop (22) connected to the second output port (14). When the first loop (21) and the second loop (22) are in an independent power supply state, the first contactor (KM1) and the second contactor (KM2) are switched on and the third contactor (KM3) is switched off. The application of the train power supply circuit to an electric multiple unit can achieve different power supply modes through different states of switching.