Abstract: The synthesis of ethylene oxide in three phase slurry reactor is studied in a kind of liquid heat carrier. This kind of liquid medium is an anti oxidation solvent with high boiling point, good heat stability and low vapor pressure and contains poisonous substance to silver catalyst below allowance. The experiments using two kinds of solvent, which were called No.1 and No.2, were screened out. Due to the fact that these solvents are used in special fields, the physical properties, especially for ethylene oxide synthesis in three phase slurry reactor, are very lacking. Some physical property data about the solvent No.2 including density, viscosity, surface tension and specific heat capacity have been studied. For the determination of surface tension the maximum bubble method was adopted. Pycnometer was used for density determination. Viscosimeter was used for viscosity determination. Dewar bottle was used for specific heat capacity determination. By least square correlation equations between temperature and physical property data the experimental data were correlated. These experiment results provide necessary data for the study of synthesis of ethylene oxide in three phase slurry reactor.