Abstract: Due to the discontinuity of coal production, the belt conveyor is often in the running state of no-load, light load and rarely full load. This causes a waste of electricity and exacerbates the wear and tear of equipment. At present, the method to solve this problem is to control the velocity of belt conveyor according to the information of coal flow. However, the current method seldom considers the connection relationship between the upstream and downstream of the coal flow between the belt conveyors, the installation position of the coal flow sensor, the detection error, the information lag and the timing sequence relationship in the process of belt velocity change. In order to solve the above problems, according to the relationship between driving power, running resistance and belt velocity of belt conveyor, the optimal energy-saving running condition and the optimal energy-saving rate of belt conveyor are obtained. According to the optimal energy-saving running conditions, the relationship between upstream and downstream connection mode of belt conveyor and material balance, rated transportation quality and rated belt velocity, the minimum belt velocity and optimal belt velocity control coefficient under the optimal energy-saving control conditions of belt conveyor are obtained. According to the installation position of the coal flow sensor, the detection error, the information lag and the time sequence relationship of the belt velocity change process, an energy-saving optimal control method of belt conveyor is proposed. According to the coal flow information of the upstream belt conveyor, this method calculates the given curve of the belt velocity change of the downstream belt conveyor under the optimal energy-saving control condition. The adjustment of the belt velocity of the downstream belt conveyor is realized according to the curve. By using the simulated energy-saving experiment platform of belt conveyor, the optimal power saving rate is tested. The results show that the optimal power saving rate of belt conveyor under the optimal energy-saving running condition is 20.9%-76.5%. However, in the actual transportation system, because the belt velocity can not be adjusted continuously, it is impossible to achieve the optimal running condition. The energy-saving optimal control method of belt conveyor is apply to the control of the No. 101 main hoisting belt conveyor in Ningtiaota Coal Mine. And the result shows that this method realizes the smooth connection of coal flow, and the power saving rate is 9.1%-43.9%. The energy saving effect is obvious.