Abstract: In order to improve the displacement efficiency and success rate of CO2 flooding,research has been carried out to predict the pressure and temperature distribution in the wellbore,which affects the displacement efficiency.In view of the special physical properties of CO2,Span-Wagner equation of state,based on the dimensionless Helmholtz energy,has been adopted to establish a model to predict the distribution of temperature and pressure while injecting CO2,calculated by iterative coupling with CO2 physical parameter and pressure as well as heat.The model can predict the bottomhole temperature and pressure accurately.Compared with the well site data of Well Cao 8 in Jiangsu Oilfield,the error of predicted temperature less than 1%,and the maximum error of pressure less than 1.6%,it can meet the requirements of field application.Moreover,the sensitivity analysis can be done through the research of effecting regularity on the bottomhole pressure and temperature produced by injection temperature,injection pressure,injection rate and time,etc.Study shows that model is very accurate,and it can guide CO2 flooding,fit for prediction and analysis of wellbore temperature,pressure and related affecting factors in supercritical CO2 drilling and fracturing.