The apple leaf miner, Phyllonorycter ringoniella(Lepidoptera:Gracillariidae),is an important pest of apple trees in Japan, Korea and China. It is very important to know the development time of overwinter pupae for predicting the adult spring emergence in apple orchard. In total 556 damaged leaves caused by P. ringoniella were collected three times in two locations, Pohang and Mungyeong, and then were reared in five incubators with 10, 15, 20, 25, and 30℃, RH 60±5%, and a photoperiod of 16:8 (L:D) h, respectively. There were larvae, pupae of P. ringoniella and its parasitoids inside these damaged leaves. Larval population was 44% inside the curled leaves, but found all dead. Pupal population was 41%, but 41% were found dead. Parasitism was 14.5% ranged from 4.5 to 17.9%. This means that the winter survival was only 23.9%. Surviving pupal developmental rate was linearly related to the temperature treated. Lower threshold was estimated to 3.58℃ with degree-day accumulation to adult emergence of 153.8 DD. From this information, adult emergence was predicted during early April. However this estimation was only based on the partial data from which current experiments are on-going. Further sophisticated research outcome will produce better understanding of the overwintering moth development and its modeling.