Necking force is the main failure factor to the unstabitily of the thin-wall cylindrical parts. In order to improve the calculation precision of the necking force , Сторожев and Унксов separately put forward two different calculation methods about the necking force of the thin-wall cylindrical parts which take into consideation the thickness changing, the hardening effect and the friction function. In this paper, the results of the two calculation methods are analyzed by example,and are compared with experimented data. The results of two calculation methods are close to each other, and tally with experimented data.