In hybrid electric vehicles, there is a set of electricity generating system. This system was modified to meet requirements of vehicle-mounted power plant. The new system is mainly composed of engine, generator, planetary gears, motor, battery, transfer case, control system and etc. and the planetary gears mechanism has two sets of planetary, control system includes vehicle controller, engine controller, motor controller, and inventor. This system can perform the functions which include vehicle driving, generating with vehicle ruining and generating with vehicle stopping. It can meet requirements of special purse vehicles.