Abstract: The theoretical solutions of a casing-cement-stratum system in theformation stress field are studied using the elasticity theory. The problem isdivided into two relatively simple subproblems.The cased hole system is a cylindrical layer structure and theloading state of each layer is similar. The solutions of two planestrain basic problems can be used to obtain the analytic solutions oftwo subproblems through the continuity condition of displacement. The theoretical solutionsfor the stress distribution in casing--cement and stratum system arefinally obtained by applying the superposition principle.