Abstract: A simple practical method of calculating residual oil saturation of thermal steamflooding process is proposed. Principally this method combines the iaboratory results with Bursell—Pittman relation, establishing a relationship amongst residual oil saturations with the tem perature,oil viscosity and the physical properties of Jhe reservoirs, which can be used to calculate restdual oil saturation of steam flooding process. This method is applied in NO. 6 District. No. 9 District, Hong Shuan Zui District and Fong Cheng District of the KARAMAY oil field. The results are consistent with some other related studies. The calculated residual oil saturation can be used as the parameters for reserve，numerical simulation and the design of the development project .