Aiming to study the influence of formation water invasion on the well bore temperature and pressure in SC-CO2 (supercritical CO2) drilling with coiled tubing, this paper builds up a wellbore flow model with formation water invasion in SC-CO2 drilling with coiled tubing, based on the comprehensive investigation of the influence of viscosity, density, thermal conductivity, isobaric heat capacity and Joule-Thompson coefficient of SC-CO2. The wellbore temperature and pressure distribution were calculated by the method of coupling among these parameters. The results show that the bigger the rate of invaded formation water and the bigger the density of mixed fluid, the bigger the convective heat transfer coefficient in the annulus.