The invention relates to a dual-power special-purpose car chassis and a control method. The dual-power special-purpose car chassis comprises a car frame, a conventional traveling system, an uploadingwork system and a control system. The car frame comprises two longitudinal beams, multiple crossbeams at the front end, the middle part and the middle-back part of the car frame, a low-position smallcrossbeam and a side-placed spare wheel carrier. The low-position small crossbeam and the side-placed spare wheel carrier are arranged at the position of a spring seat of a back plate of a rear axle of the car frame. The conventional traveling system comprises an engine, a gearbox with a one-shaft power take-off device, a driving shaft and the rear axle. An output end of the engine is connected with an input end of the gearbox. An output end of the gearbox is connected with the rear axle through the driving shaft. An output end of the one-shaft power take-off device is connected with an inputend of the uploading work system. Through the control system, low power is outputted by an engine when a car is driven at low speed. High power is outputted by the engine during upload work and high-speed driving. The way of thinking about the layout of double engines adopted by upload work of a special-purpose car is changed. The arrangement of the whole car is simplified while the cost of the whole car is reduced.