The casing tubes for shale-gas-wells are Baosteel’s advanced products and have found their huge market. However, the mechanisms of its superior anti-collapse property are unclear. This not only limits the applications of Baosteel’s current products, but also makes it difficult to develop new products more suitable for shale-gas-well applications. This research aims to develop a collapse strength model corresponding to the Baosteel testing to understand the mechanisms of casing collapse, and hence to improve product design for the shale-gas-well market. The research outcomes would also help end-users comprehend the possible failure of such casing products.