Abstract: The collapse pressure of the double-layer oil casing is obtained via the FEA method so as to provide a theoretical basis for the analysis of the casing-damaged well. The result reveals that under the conditions of the damaged well,the external collapse pressure of the double-layer casing is much lower than that of the inner casing.Accordingly relevant necessary measures should be taken to avoid re-occurrence of the above mentioned problem,including improving the cementing quality of the cement,improving cement anti-height performance,and enhancing annulus pressure detection.