Abstract: In order to reduce the mine coal reserves calculation error caused by human factors and improve the relability and precision of the calculational results, a grid method was put forward to calculate the coal reserves based on GIS. The coal seam thickness realized by grid data was also obtained by Kriging and function of grid data of SURFER. Further, the data of coal floor contour were conversed into discrete elevation data by DTM module of GIS software, and the grid data of dip could be gotten by function of terrain modeling in the calculus module of SURFER. Computation parameters were assigned automatically to each grid cell by MAPGIS, and th e resources reserves were obtained by the spatial overlay. The results showed that the calculation reserves increased about 12. 6% and 33% respectively compared wit h geological block method and mine geological report data, and the data were much closer to the actual production.