1. A method for encrypting a 3D model file, comprising the following steps of: reading data of the 3D model file, the 3D model file comprising a plurality of triangle meshes, the data comprising corresponding coordinates of vertexes of each triangle mesh; selecting at least one triangle mesh and shifting the coordinates of the vertexes of the selected triangle mesh by a vector; filling a gap generated from shifting the vertexes of the selected triangle mesh for generating a revised 3D model file; and storing the revised 3D model file for generating an encrypted 3D model file.