Triangular mesh models are widely used in various fields and develops rapidly. In order to preserve the local geometric features of the mesh model, and at the same time can better keep the edge and texture details while smoothing and denoising, a partial differential equation smoothing method based on Laplacian is came up, and it can get good denoising effect. In order to transmit and operate three-dimensional data more conveniently, an eigen-decomposition and spectral compression method based on Laplacian is came up, and it can realize the compression of the model.