Abstract: Vacuum insulated casing is a new oil well casing developed in recent years, and its good insulation properties have been proved by the results of ground tests. But it remians unadressed whether it can work as insulated casing for heavy oil thermal recovery. So it is necessary to study the strength and insulation characteristics of the casing. Based on the data of actually adopted steam, results of well casing heat transfer, vacuum insulated casing’s structure and thermal elasticity theory, the internal and external strength of vacuum insulated casing is calculated. The stresses of internal and external casing at different depths are calculated, and the factors influencing the safety of vacuum insulated casing are identified, including well depth, injected stream’s temperature. This research provides theoretical basis for proper use and further improvement of vacuum insulation casing, and a reference for the correct implementation of the cementing process.