Abstract: Addressing the hot issue of calculation of the oil casing external collapse-resistance, 10 pieces of the Φ114.3 mm×8.56 mm 140V casing are selected and subjected to both geometric dimension measurement and mechanical property tests.And the pipes are also subjected to the collapse test to determine their collapse resistance.Meanwhile based on the consideration of the geometric defects and the actual mechanical properties of the pipes, a FEA model for calculating the collapse strength of the casing is set up.After comparing the results of the simulation, the theoretic calculation and the tests, it is demonstrates that the result of the simulation is close to that of the tests, showing a deviation of -0.77%~+7.0%, whereas the theoretic calculation result shows an obvious error, i.e.a deviation of 23.84%~37.56%.Thanks to the above mentioned model, the influence by the wall thickness unevenness and the ovality on the collapse re-sistance of the said oil casing is analyzed.