The new working fluids were composed of three salts such as lithium bromide, lithium nitrate and lithium chloride and added two organic surfactants (ethylene glycol, ethanol amine) of 1∼5wt%, respectively. The solubility data were obtained in the temperature range 253.15∼363.15K, The vapor pressure data were correlated as an Antonio's equation. The properties of working fluids were invstigated as functions of surfactant contents. As the surfactant contents were increased, the crystallization temperature of working fluids was determined to decrease. However the vapor pressure was increased with surfactant contents slightly.