The development technology of fin-and-tube heat exchanger has gained many years of practical experiences and established a complete and detailed database from the test results of heat exchangers from the laboratory of ITRI. With the data source from testing, we build the simulation software to be used for the fin-and-tube heat exchanger under Windows environment. This software has the potential power to save a great deal of time and costs resulted in trial and error during the processes in heat exchanger design and development for manufactures. This technology presents the model to evaluate the heat transfer rate and pressure drop of the air-cooled heat exchangers. To effectively improve the performance of air-cooled heat exchangers, passive enhancement techniques are often employed. The methods are (1) by using enhanced fin/tube surfaces; (2) by increasing total surface area; (3) by increasing the effective mean temperature difference between the air flow and refrigerant flow. Detailed description of the proposed model is described in this report. The calculated results of the proposed model agree with experimental data.