Steam assisted gravity drainage（SAGD）technology is applied to develop heavy oil reservoirs. CO2 can reduce the viscosity of heavy oil and the heat loss of the steam chamber can be reduced，and thus oil recovery may be enhanced by this technology. Due to the limitation of experimental environment and equipment，the maximum temperature of reaction kettle is no more than 150 ℃. Thus the solubility of CO2 in super heavy oil and its impact on decreasing viscosity beyond 150 ℃still require further discussion. In terms of these issues，a high temperature and high pressure resistant heavy oil mixing apparatus was designed，and the solubility of CO2 in the super heavy oil and the effect of dissolved CO2 on the density and viscosity of the super heavy oil were measured at different temperatures and pressures. Laboratory tests show that the solubility of CO2 becomes significantly low at reservoir temperature of 200 ℃，and the viscosity and relative density of the super heavy oil will not change with the pressure. The viscosity and density of the super heavy oil saturated with CO2 are much lower than those of the degassed crude. The dissolution characteristics of CO2 and the mining effect of heavy oil were numerically simulated by CMG software，and the recovery rate of heavy oil reservoir was improved remarkably. It shows that the super heavy oil reservoir can be developed at reservoir temperature of 200 ℃.