Abstract: Researches were carried out to reveal some heat exchange characteristics of non-azeotropic refrigerants during condensation, and understand the change of temperature difference (between refrigerant and heat transfer fluid).Firstly, a model of refrigerants condensation was built, and refrigerants properties parameters were decided for the air-conditioning operation.Secondly, the equation of state of refrigerants was used for computing and obtaining some relationship between temperature and enthalpy, and the temperature differences between those refrigerants and heat transfer fluids were obtained.Through analyzing those temperature differences, a rule of temperature change was found.The rule may be helpful to designing condensers in air-conditioning unit or heat pump unit.