Abstract: Supercritical three-phase methanol synthesis on C302-2 catalyst was studied in a mechanically agitated slurry reactor with paraffin oil as the inert liquid medium and n-hexane as the supercritical medium under the operation conditions of the temperature ranging from 235 ℃ to 260 ℃, the pressure ranging from 6.0 MPa to 7.0 MPa and the mass space velocity ranging from 450 L(STP) •(kg cat)^-1•h^-1 to 1600 L(STP) •(kg cat)^-1•h^-1.The effects of operation conditions on the conversion of carbon monoxide and outlet methanol mole fraction were discussed in detail.The result showed that both the conversion of CO and methanol mole fraction decreased with the increasing mass space velocity and temperature under the condition of supercritical n-hexane.In addition, three-phase slurry bed methanol synthesis with and without supercritical n-hexane was compared.CO conversion and methanol mole fraction under supercritical condition were higher than those at three-phase slurry bed without supercritical n-hexane.