From the angle of the actual metrology test and maintenance by the development, production, operation and maintenance of modern aircraft, this article focuses on analyzing the reason of overtolerance, and proposes one method of the software correction by air data test set pointedly, and this method lays an important foundation of practice for air data test set meeting high quality technical requirements after the correction of air data test set. Experimental results show that this method of the software correction is very effective and it can provide technical support for metrology and correction of air data test set.