Abstract: Addressing the fact that the equivalent stress criterion is no longer suitable for measuring the collapse strength of a peforated casing，a non-linear bulkling technique is adopted to establish a 3-dimensional finite element model of the Ф177.8 mm×10.36 mm 895.7 MPa peforated casings.Collapsing patterns of the casings before and after peforating are compared.The influences of the changing of different peforating diameters，distribution densities and phase angles on collapse strengh of the peforated casings are analyzed.The analysis leads to the following conclusion.The radial displacement of a casing non-linearly increases with the increasing of the load.The peforating diameter has significant influence on the collapse strength of a peforated casing，i.e.，the collapse strength decreases when the peforating diameter increases.The peforating density has certain influence on the collapse strength of a peforated casing，i.e.，the collapse strength slightly decreases when the peforating density increases.The phase angle has no obvious influence on the collapse strength of a peforated casing.