Abstract: Summarized in the paper are the present situations concerning researches on the expandable casing both at home and abroad,revealing the big gap between China and relevant developed countries in the field of the manufacture technology for the hi-performance expandable casing. Also discussed are material type selection,property requirements and objective for structure design of the steel as used for the expandable casing in accordance with different operation conditions. Furthermore,the development trend of such product is forecast,and the importance of it to domestic oil/gas exploration and exploitation field is emphasized. Finally,it is suggested that localization of hi-end expandable casings be further geared up so as to provide the equipment support to the critical technology of welldrilling with the expandable casing that is badly needed for domestic deep-ocean well-drilling, and exploration and exploitation of the oil/gas deposits in West China area.