Digital Mine is an important research content in the mineral field, the core is tunnel. A new three-dimensional data model of tunnel has been put forward, semi-tunnel was as volume element to construct the three-dimensional tunnel. According to this volume element, five basic modeling elements were abstracted to form the semi-tunnel. On the basis of semi-tunnel, it can build a model of simple tunnel, complex tunnel, composite tunnel and three-dimensional tunnel network. Then, the paper summarized data structure by analyzing the topological relationship between these tunnels and five elements. In terms of above new data model, the complete underground mine tunnel network will be constructed based on data structure. Thereby it can promote the development of theory of Digital Mine.