In order to improve the orientation precision of the workspace measurement posit ion system (wMPS),a new calibration method based on data weighted fusion is prop osed in this paper.The method adds three-dimensional coordinate constraint of laser tracker and light plane constraint of wMPS to obtain a higher orientation precision.The error transfer function is derived .The uncertainty of laser tracker and wMPS is converted into weight to orientate.The DLT algorithm which is usually used in photogrammetry coordinate transformation is used creatively to calculate the ini tial value of the RT from the single wMPS transmitting station coordinate to the global coordinate.The al gorithm is proved effective and is used successfully.Finally the data weighted fusion method is c ompleted .Simulation results show that with this method,error of translation is within 0.09mm and er ror of rotation is within 2.4＂.The experiment is performed in a 8m×5m×4m space with wMPS orientated by this method. The accuracy of point measurement is better than 0.21mm,while the accuracy of r uler length measurement is better than 0.1mm.The results of experiment show that method proposed in this p aper has higher orientation precision compared with traditional orientation method which uses kn own control points.