1. A method for reconstructing a three-dimensional model, adapted to build a three-dimensional model of an object, comprising: obtaining a plurality of first depth images of the object; dividing the first depth images of the object into a plurality of depth image groups according to linking information of the object, wherein the linking information records location information corresponding to a plurality of substructures of the object, each of the depth image groups comprises a plurality of second depth images, and each of the substructures corresponds to the second depth images of each of the depth image groups; building a local model corresponding to each of the substructures according to the second depth images and the location information corresponding to each of the substructures; and merging the local models corresponding to the substructures according to the linking information of the object, so as to build the three-dimensional model of the object.