ln order to study the excess enthalpies for mixtures containing supercritical component, a flow isothermal microcalorimeter has been used to measure the excess molar enthalpies of carbon dioxide + methanol system at 308.15K and 7.5∼7.9MPa. The verification of the calorimeter was made by measuring the excess molar enthalpies of methanol + water(exothermic system) and hexane + cyclohexane(endothermic system) at normal pressure and normal temperature. A modified mixing rule Peng-Robinson equation of state was used to correlate all of HE data measured in this work and fair correlation results were obtained.