Under the carbon capture, utilization and storage (CCUS) well, the oil well cement will be carbonized and corroded due to the long-term action of downhole high temperature, high pressure and highly acidic fluid, resulting in the failure of the cement sheath. In order to simulate the carbonation and corrosion environment of CO2 geological storage well, the main single ore mineral calcium silicate (C3S) of oil well cement was placed under different temperatures (30 ℃, 60 ℃, 90 ℃) and sealed 8.0 MPa gas or liquid phase CO2 carbonization environment. XRD and TGA were used to analyze the influence of C3S in cement single ore by CO2 corrosive environment. According to the infiltration theoretical model of unsteady Fick diffusion, a mathematical model of the quantitative analysis results of corrosion products and corrosion age was established, and the product formation coefficient of C3S after being corroded by CO2 was obtained by fitting, so as to evaluate the influences of different CO2 corrosion factors on C3S. The results show that the increase of temperature significantly aggravates the corrosion of C3S and leads to the dissolution phenomenon in the gas phase environment of CO2. While in the liquid phase environment of CO2, the high temperature (90 ℃) makes the C3S hydration reaction intensify, forming a retardation layer and slowing down the CO2 corrosion rate to C3S.