A power output device of a subsoiling land preparation machine comprises an engine, a transmission shaft, a transfer case, a front gearbox and a rear gearbox which are installed on a frame, an output shaft of the engine is connected with an input shaft of the transfer case, an output shaft of the transfer case is connected with an input shaft of the front gearbox, an output shaft of the front gearbox is connected with an input shaft of the rear gearbox through the transmission shaft, the engine transfers power to the front gearbox, the transmission shaft and the rear gearbox sequentially through the transfer case, and an output shaft of the rear gearbox transfers the power to an agricultural implement. By the aid of the power output device of the subsoiling land preparation machine, the variable-speed, variable-torque and interrupted power transfer can be achieved, the best match between the device and the engine can be achieved, the revolving speed and the torque of the whole vehicle are effectively controlled, the transmission system overload is prevented, the torque and revolving speed changing range for power output is large, the output power is strong, the power output device can be adapted to frequently-changing terrains, during driving, the power transfer is interrupted through neutral positions of the gearboxes to stop operation of the agricultural implement, the energy consumption is reduced, and the implement is protected.