1. A line guided three-dimensional model reshaping method, comprising: step S 100 , creating a two-dimensional (2D) line database: extracting a 2D contour of an object from an Internet image containing a single object by using an image segmentation algorithm, and creating a 2D line database by selecting a 2D contour or a 2D main skeleton based on symmetry of the object; step S 200 , retrieving and suggesting a 2D line: selecting, by a user, an editable region in an input three-dimensional (3D) model; extracting a 3D editable line; and suggesting a corresponding 2D contour or skeleton in the 2D line database based on a shape context descriptor and a shape feature; and step S 300 , contour matching and parametric deformation: establishing a point-to-point correspondence between the 2D contour or skeleton and the 3D editable line; and reshaping the 3D model by using a parametric deformation algorithm.