Abstract: In view of problem of low precision and poor adaptive capacity of boundary conditions of existing calculation method for mine reserve, subdivision algorithm of improved triangular prism was proposed: triangular prism was divided into different cones according to different rules and combined with top surface, undersurface and triangle cut section of the improved triangular prism; reserve range was got according to border control conditions, and volumes and reserves of all improved triangular prisms within the control range were calculated combining with geostatistics.