Abstract: Taking Harwusu Open-pit Mine as background, based on the technical principle of single-station differential pseudo-range differential technology, the design method of differential auxiliary positioning system is studied, which includes the location selection of differential positioning base station and the network arrangement of differential positioning system. Drilling machine drilling technology and construction vehicle positioning technology based on differential positioning technology are studied. Differential positioning technology improves the production efficiency and safe production level of Harwusu Open-pit Coal Mine.