In terms of the long period, high cost and importance of the civil aircraft landing gearing sampling program, this paper discusses methods of confirming sample size based on IP44, which is the core of the civil aircraft landing gearing sampling program. In addition, this paper suggests that choose the sampling model according to the actual aircraft’s servicing time interval and operating environment. On this basis, using linear analysis method forecast failure tendency and establish the assumption verification standards of the landing gear restoration task interval, which verify the suggested analysis methods. The results turns out that methods in this article could justify the rationality of the landing gear restoration task interval and provide a guidance on domestic researching and developing civil aircraft landing gear restoration program independently. Furthermore, this project fills the blank domain of the landing gear restoration sampling program for domestic civil aircraft.