Aiming at the problem of shear-induced casing damage caused by standard layer shale soaking water, the theory of rock mechanics is used to establish the fluid-solid coupling calculation model of the formation-cement ring-casing of the standard interval shale interbed, obtaining the strain and deformation changes of casing shear damage, and puts forward the casing logarithmic strain exacerbated area should prompt adoption of reasonable measures to slow down the casing damage. Three-level orthogonal numerical simulation experiments were carried out for the five factors affecting casing damage, the simulation results show the critical strain data of the casing damage and the true strain data of the casing under the influence of five factors. According to the statistical principle, the predictive mathematical model of the critical strain and true strain prediction of the casing is obtained by the multiple regression method, realize the prediction of the strain state of the casing under actual working conditions is realized, and then realize casing damage early warning.