A phytosociological survey was carried out on Zelkova serrata forest in Aomori Prefecture. Based on the floristic composition, the following three associations were recognized. The distribution pattern of the three associations is closely related to the precipitation level, the temperature and total snowfall. Parabenzoino praecocis - Zelkovetum is distributed only in the eastern part of this prefecture, i.e. around Hachinohe city and Sannohe town, where precipitation and snowfall is less than in other parts of the prefecture. Cacalio bulbiferae-Zelkovetum is distributed widely in Aomori Prefecture. This association is found in areas where the annual precipitation and snowfall are higher. Aceri glabri-Zelkovetum serratae is found on windy sea-facing slopes, where it is warmer than other areas, with the annual mean temperature over 10℃. The floristic composition of these associations was compared with that of Zelkova serrata forests investigated by other researchers. The northern limit of distribution of these Zelkova serrata forest associations is Aomori Prefecture.