Abstract: Traditionally, the calculation of reserves usually adopts the geometrical average method to count orebody volume and uses the average grade of chemically analyzed samples to represent the whole grade of ore block. However, such calculation accuracy cannot satisfy the demand of production. The accuracy of volume calculation may be im proved by the three-dimensional orebody model; while the accuracy of grade assessment can be improved by estimation for random location of orebody with space interpolation. This paper introduces a kind of hybrid data model (Wireframe-Block) suitable for orebody reserves calculation, which gains wireframe model from section data of orebody and then generates block model on the basis of the wireframe model. The reserves of a certain orebody is calculated by inverse distance method. The result shows that the calculation of orebody reserves with space interpolation based on Wireframe-Block is practical.