Under the background of the “dual carbon” target, exploring new paths for industry restructuring to reduce carbon emissions and increase efficiency, and developing new high-quality productivity for CO2 high-energy utilization are hot topics in CO2 emission reduction research. To determine the mechanism of CO2 phase change induced cracking and expand the application of CO2 phase change induced cracking engineering. Safety and environmental advantages demonstrated based on the multiphase change characteristics of CO2 and energy utilization, a new type of deep drilling supercritical CO2 heat exchanger is proposed. Taking CO2 at 25 ℃ as the research object, a simulation scheme was designed using fluid simulation to simulate different water temperatures as heat carrying fluids, revealed the gas-water heat transfer mechanism under the coupling effect of hydrothermal fluid and CO2.The reliability of heat transfer in CO2 heat exchangers has been verified through experimental analysis. The results that as the temperature of the hydrothermal fluid increases, the heating rate of CO2 is positively correlated with the temperature of the hydrothermal fluid. For every 1℃ increase in water temperature, the temperature of CO2 increases by 0.9℃, the temperature of the water stream decreases gradually with the increase of CO2 heat absorption, dissipation temperature of hydrothermal fluids is proportional to CO2 absorption temperature. The heat transfer coefficient of hydrothermal fluids increases from 1790W/m2?K to 2090W/m2?K. The heat transfer coefficient of hydrothermal fluids gradually increases with the increase of initial water temperature, The heat transfer coefficient of CO2 is directly proportional to the heat transfer coefficient of hydrothermal fluids. The CO2 phase change heat absorption temperature showed an exponential growth trend with the increase of water temperature, and the liquid CO2 heat transfer coefficient was inversely proportional to the trend of the gas CO2heat transfer coefficient. The maximum pressure of CO2 inside the pipe increased from 131MPa to 199MPa, the pressure change goes through a phase of thermal expansion of liquid CO2, a phase of thermal expansion of gasCO2 a phase of phase change energization, and a phase of pressure stabilization. The heat absorption of CO2 is positively correlated with the initial water temperature, and the power of the water flow heat source gradually increases with the increase of water temperature. The power of the water flow heat source is proportional to the water temperature. The effectiveness of the deep drilling supercritical CO2 heat exchanger was verified through the establishment of correlation equations and experimental analysis, providing a basis for the design of supercritical CO2 heat exchangers.