Abstract: Taking MDY-100 truck mounted drilling rig as an example, the technological characteristics and load characteristics of drilling rig are analyzed. Starting from energy saving and optimal power matching, this paper analyzes the problems existing in the application of the limit power control system of engine in the matching of power system of the drilling rig. According to the load characteristics of drilling rig, a time-sharing power matching method is proposed, and the rationality of the parameters is verified by the combination of dynamic simulation and experiment. Compared with the traditional limit power control method, the system has the advantages of high speed rigidity, good process adaptability and high fuel economy.