The invention discloses a high-voltage integrated control system and method for a new energy bus. The system comprising an energy storage system module (1), a low-voltage power supply and control module (4), a main loop module (5), a DCDC loop module (3), and an off-board charging socket module (6), wherein the off-board charging socket module is connected with the energy storage system module, the off-board charging socket module sends a charging connection signal to the energy storage system module and a vehicle control module (45) for starting a charging process; the DCDC loop module includes a DCDC contactor module (31), a DCDC module (32), and a DCDC precharge module (33); the DCDC contactor module and the DCDC precharge module are connected in parallel and connected in series betweenthe energy storage system module and the DCDC module; and the DCDC module is connected to a battery module (41). By the adoption of the high-voltage integrated control system and method for the new energy bus, a manual gate is not closed during charging, and power supply is directly converted by high voltage via a DCDC power source, and power is supplied to a low voltage electronic module that needs to work during the charging, thereby avoiding a risk of power shortage of the battery; and cost and complexity of the system are reduced by reusing the DCDC module.