In view of the problems of complicated calculation process, tedious operation, low real-time leading to unstable coal quality, large fluctuation and so on in the coal blending operation of open pit coal mines, this paper proposes a multi-objective automatic coal blending method for open pit coal mines to achieve accurate control of coal blending in open pit coal mines.The basic idea is to set parameters such as target range of coal quality, upper limit of impurity content, working table time of electric shovel and coal mining volume in combination with the current situation of the mine.According to the shovel coordinates, obtain the coal quality and impurity information of each shovel loading working face, comprehensively consider the shovel capacity, upper and lower limits of target coal quality, upper and lower limits of impurity content and other constraints, build a multi-objective automatic coal blending mathematical model, and call the CPLEX solver to solve the automatic coal blending mathematical model through the C++ language of Visual Studio to obtain the coal blending scheme.At the same time, the position of the shovel is monitored in real time, and the coal discharging scheme is adjusted according to the change information of the coal quality and impurities in the shovel loading face, and the method is applied to a large open-pit mine in Inner Mongolia.The research results show that the method can meet the requirements of multi-objective coal blending in seconds, achieve balanced allocation of high and low quality coal mines, and ensure the safety and economy of mine production.