Abstract: It is important for properly selecting the casing to understand the factors affecting the collapse strength of a new type of casing (TP130TT Ф152.4mm ×16.90mm) with high collapse strength. The effects of the casing defects (uneven thickness and ellipticity) and non-uniform loads on the casing collapse strength were analyzed by the finite element method, and the results showed that the collapse strength decreases with the increasing of ellipticity and non-uniformity of the casing thickness, while it still firm enough to withstand the collapsing load under non-uniform load conditions.