Three japonica cultivars with different cold tolerances in cold region, ‘Dongnong 428’, ‘Songjing 10’ and ‘Longdao 7’, were used as materials to study the change rules of SOD, POD and CAT activity in functionalrice leaves after cold stress during booting stage. The results showed that SOD, POD and CAT activity in functionalleaves of the three cultivars all presented the tendency of rising at first then declining as the increasing of stress day.There were a larger variance of enzymatic activity among cultivars. SOD, POD and CAT activity of the three culti-vars all reduced after stress, and obvious cold injury symptoms appeared in the leaves. ‘Dongnong 428’ with thebetter cold tolerance had higher CAT activity. SOD and POD activity during recovery phase had no significantchanges between each treatment. The CAT activity of ‘Songjing 10’ with the weakest cold tolerance and ‘Longdao 7’ with moderate cold tolerance were all higher after stress but ‘Dongnong 428’ were lower.