Vapor-liquid equilibrium(VLE) data are essential when using mixtures as refrigerant. At isothermal conditions, near room temperature, VLE data of two binary mixtures containing 1,1,1,2,3,3,3-heptafluoropropane(HFC-227ea)+1-chloro-1,2,2,2-tetrafluoroethane(HCFC-124), HFC-227ea+1-chloro-1,1-difluoroethane(HCFC-142b) were measured in this study. Little difference in boiling point temperature between each component features both mixtures. Temperature, pressure, and liquid phase composition were measured and vapor phase composition was determined with an equation of state. Both mixtures showed nearly ideal phase behavior and were found to be non-azeotropic mixtures in spite of little difference in boiling point temperature. This result of study shows the fact that the formation of azeotrope can be predicted with not only normal boiling point temperature or vapor pressure but with non-ideality of mixture together.