Abstract: Casing collapse failure is regarded as a chronic serious technical problem encountered with in oil field operations.Addressing this issue a non-API WSP110T hi-collapse strength casing is developed.Presented here in the paper are the design principle,the main development activities and the test result related to the casing.The evaluation of the newly-developed product by relevant authorities shows that its collapse strength is 25% higher than what specified in applicable API specification,which leads to the conclusion that substituting the said casing for its API counterpart will prolong the service life of the oil well and enhance the overall benefit of oil field exploration,having a great potential market.