Abstract: A data compress idea is put forward by considering the judge accordance of the angle between two normal lines of the triangular plane face.So that the corresponding algorithm of the data compress is given by calculating the angle between two normal lines.The acceptance or rejection of a point is determined according to the comparison between the biggest angle with the defined threshold.As a case study,the Kongzi portrait in Tongji University is scanned and the real three dimensional model is established.The data compression aim to the Kongzi portrait is conducted to achieve the realization of the given method.In order to prove the feasibility of the method and the quality of the compression,several evaluation results are then analyzed same with the case data.