In this paper the level-set method is introduced to mesh simplification of the three-dimensional model, especially for cultural heritage. First, constructs a signed distance function, the zero set of which define is the surface. Then, introduces a energy functional and minimizes it to derive a second order geometric partial differential equation ( GPDE) in the level-set formulation. Thus, the mesh simplification process is transferred into volumetric diffusion process of an implicit model. This method is used for simplification of digitalization of large scene and relics in cultural heritage. Finally, the level-set mesh simplification algorithm are compared and analyzed with mesh simplification algorithm based on point-collapse on the visual quality and geometric error. The experiment shows that it can be applied any topology of mesh .Even model is large-scale simplified, it is still able to maintain a considerable number of important geometric features and better overall visual effect while maintaining a low error level.