Non-uniform frost is formed on the fin-tube heat exchanger of heat pump when moist air below 0℃ is flowing over its cold surface. Formed frost acts as thermal resistance to make heat transfer rate decrease and blocks air flow space to increase air side pressure drop. Frost prediction on the heat exchanger leads how to delay frost in order not to increase defrosting energy. Non-uniform frost pattern on the heat exchanger was predicted by using segment by segment method for the heat exchanger. Local heat transfer rate for each segment was obtained by applying ε-NTU method. The proposed model was validated by comparing the predicted values with measured data for the frost on fin-tube heat exchanger. Predicted local and average frost thickness, average air side pressure drop, and heat transfer rate agreed with the measured data within 16.5%.