Abstract: Degradation kinetics of ascorbic acid(AA) in kiwi fruit juice was studied in order to provide theoretical basis for controlling ascorbic acid loss. The method was adopted to spur ascorbic acid degradation by controlling temperature and regulating pH value. The results show that ascorbic acid degradation in kiwi fruit juice is very complex. There are lots of AA degradation pathways, among which the aerobic one is the primary one. A instance maybe occur that ascorbic acid is degraded in other irreversible ways without dehydroascorbic acid(DHA). Yet it is not the dominant one. Anaerobic degradation speed of ascorbic acid in kiwi fruit juice is slower than that of the aerobic degradation, and aerobic degradation speed increases while anaerobic degradation speed changes slightly with the increase of temperature.