The invention belongs to the technical field of fluid transmission and discloses a compound transmission accelerating device. The compound transmission accelerating device comprises a base, a first transmission mechanism and a second transmission mechanism. The first transmission mechanism and the second transmission mechanism are connected through a coupling. The first transmission mechanism comprises a pipe and an evaporator. Gas is led in the pipe. A gear transmission part comprises a shell, a driving gear, a driven gear and a sailboard. The driving gear meshes with the driven gear and is provided with a first center shaft. The driven gear is provided with a second center shaft. A mast is connected to the first center shaft and connected with the sailboard. The pipe is connected with the sailboard. A connection rod mechanism is connected to the second center shaft. The other end of the connection rod mechanism is connected with a piston. The second transmission mechanism comprises an air pump, a piston, an air inlet and an air outlet. The problems that according to the prior art, vibration is generated, consequently a device is damaged or a connection part is loosened, the device can be used only by switching on a power source, and thus the device is inconvenient to use are solved.