Abstract: In-situ stress is one of the important parameters for petroleum engineering design and operation.Usually in-situ stress is obtained by direct measurement and laboratory test,the two methods are higher cost,but oil field has much more data for casing deformation,it can be used to conduct inversion and calculation to get in-situ stress.Taking casing deformation data as the premise condition,in-situ stress inversion can be made to establish the oval stress boundary mode,which is consistent with down hole conditions of casing.The square of difference between calculated maximum deformation and measured maximum deformation is taken as the optimization objective function,the inverse analysis of casing displacement can be done to obtain the maximum and minimum stresses.This method has been used to analyze Well A in Xinjiang Oilfield,the results show that,the value of actual non-uniform load can be calculated rapidly under the casing deformation conditions by this method,and the calculation result has very little error compared with the result obtained from logging data,which provides the basis for rational design of casing strings,and eliminating the casing damage,it has offered a new way to get the in-situ stress for oil fields.