The special casing is one of the key factors for geological prospecting casing drilling technology. In the process of casing drilling in geological prospecting, the special casing is used as a wire-line drilling pipe to transfer the drilling pressure and torque; after drilling, it is kept in hole as technical casing with casing function. The selection and development of the special casing structure, material and processing technology are completed through indoor tests and the effects are obvious in field application.