This paper introduces the extend caliber and collimate method, which receive the centralized axis to a appropriate caliber in collimator on many spectra. The discrete axes which are far from the center are guided to the collimator by the special design arm, extend arm can rotate and slide along the auto-collimator so that different position targets could be required. The parallel precisions between the extended axis and the original axis of collimator affect the testing precision of the which system. The extended arm programs and high precision auto-erecting are given, which not only make the problem easy, but also ensure the precision. In practice the accuracy is better than 0.01 mrad.