The necessity of the pointing accuracy measurement of scanning type infrared detecting system was described and analyzed, and a method of pointing accuracy measurement of scanning type infrared detecting system was put forward. Colligating the advantages of infield and outfield measurement，the method reduces the error caused by the detecting equipment error and improper detecting method in the whole process of measuring. The reason and the result of the error were analyzed. The method is beneficial to high precision measurement and correction of the pointing accuracy of scanning type infrared detecting system.