In the mine production process, pre-established geological models should be updated in a timely manner based on new geologic and mining data. Three-dimensional (3D) geological models of different engineering schedules can effectively visualize the spatial distribution of the ore body in real time, displaying changes in its structure and occurrence in a timely manner and thereby providing geological guidance for overall project designs. In this paper, we propose an automatic update algorithm for 3D geological body models based on an implicit function and geostatistics. With this algorithm, the ore body model can be rapidly and automatically updated according to the original ore body exploration/mining data. The effectiveness of this algorithm was tested in several cases, and the results were compared with those of traditional ore body modelling methods. The results show that the proposed ore body model construction and updating algorithm is fast, effective, and automatic and that the resulting models are smooth and free of topological errors. In addition, this method considers the existing models and incremental data, automatically and quickly extracts constraint data from incremental data, reasonably integrates or transforms existing models to make full use of them, and builds and updates more reasonable and smooth ore body entity and grade models.