Abstract: In order to effectively repair the holes in triangular mesh model,a new algorithm of hole repairing using normal vector and quadric error metric(QEM)is proposed.After finding the hole boundary,firstly we calculate the angles between adjacent boundary edges and determine whether a vertex is concave or convex using the mesh information around the hole boundary;on this basis,we find the most suitable boundary point for repair according to the principle of minimum-angle and curvature;secondly,we complete the rough hole filling according to the principle of adding triangle and the inward normal calculation method;finally,the roughly repaired triangular mesh is further optimized by means of QEM.In Visual Studio 2013 environment,for various triangular meshes with holes,we conduct experiments using the proposed algorithm and hole-filling traditional algorithms,the experimental results show that the quality of the newly added triangle by the proposal algorithm is better than other methods.