A new method is presented for developing a simulation program which can analyze the heat transfer characteristics of fin-tube heat exchanger. This method is able to describe several types of refrigerant circuit arrangement. The delivery path of air and refrigerant properties is simplified by transforming three-dimensional array into one-dimensional array. By comparing simulated results with experiment results, the deviation was 8.2%. Several fin-tube heat exchangers of different design factors and operating conditions were simulated using this program. It was shown that this program could be used for designing practical fin-tube heat exchangers.