Mesh simplification is an important stage in the surface reconstruction andthe generation of multiple LOD(level of detail) models. In this paper, the authors presenta tnesh simplification algorithm based on energy evaluation which can effectively reducethe number of triangles in a dense mesh. This algorithm is able to decimate the mesh whilewell keeping the original topological type of the mesh, and to evaluate the error of meshfitness according to the energy value, To accelerate the algorithm, a simple effective sam-pling method is employed. In addition, this algorithm is highly autornatic to support theconstruction of the LOD models.