Casing damage has been frequently occurring in the oilfield development process，especially in the late period of the development.Casing is damaged by various causes，including both geological and engineering factors.To understand the causes of casing damage，and to take effective measures to protect the casing，a comprehensive analysis is carried out on the formation geology and down-hole conditions.Firstly，the mathematical-physical models are established corresponding respectively to the elastic，plastic and fluid-solid coupling medium under the perforating conditions，by considering the combination of casing，cement and formation as an elastic or plastic medium.Secondly，a simulation analysis is conducted on the casing forces impact by perforating，cement and formation lithology and stresses.The cement elastic property and thickness may reduce the casing load.The formation plastic property and rheology have considerable influences on the casing stresses.The formation pressure changes may cause the changes of casing stresses.It might be possible to take some measurements to prevent the occurrence of casing damage，such as improving cementing quality，optimizing perforating direction，reasonable selecting injection pressure.