Belt conveyor is widely used in mining industry, constant rotational speed of belt conveyor is commonly operated in China, with low efficient and power energy waste. Based on this problem, by analyzing the relationship between the belt speed and loading capacity, fuzzy control theory and PLC control technology were used to save energy, through the collection and loading capacity, reached the purpose of the control output belt speed. Based on the calculation and assumed parameter, the result showed that energy saving rate was 13.9% after the plan, with certain energy saving effect.