All over the world is striving to economize the energy and improve the efficiency of the equipment. Due to the technological progress and the technique of energy saving is updated, Taiwan’s existing techniques of energy saving still needs to improve. For example, some developed countries regard motor-driven system’s high proportion of total consuming as focal point of energy saving, but it is not universal in Taiwan. The thesis will supply systematic approaches to motor-driven system. Systematic approaches will offer users clearer ways to judge whether motor-driven systems are efficient or not, and increase the competitive nature of markets.