Automated surface reconstruction is an extremely important technique in reverse engineering as it can reduce the time required for the reconstruction of a CAD model significantly. Although it bas been received extensive attention in literature, less break-through progress has been found till now. It is because it requires the development of many fundamental techniques before the above-mentioned issue can be investigated. This study intends to develop a procedure of automatically establishing the surface model from a set of triangular meshes. The proposed procedure includes five steps, namely, meshes simplification, quadrilateral mesh generation, establishment of the constructing curves, continuity data structure and constrained surface fitting. This paper describes the purpose, principle and algorithm for each of the five steps, and presents examples to describe the feasibility of the proposed algorithms.