Abstract: In order to probe the roles of calcium in drought resistance of plants, the soybean seedlinggrown in the solntion with different calcium conentration (0, 5, 14 mmol.L-1)were used to study theeffects of water stress (- 0.5 Mpa, PEG 600) on the activities of SOD, POD and CAT and theirisozymes in the leaves of differen calcium. The results showed that under water stress, the SOD activityincreased, the CAT activity deceased. Similar tendency of POD activity was found among the leaves ofthree Ca2+ treatments, it was "increased Becreased." The PAGE analysis showed that under waterstress condition, there were 10 bands of SOD, 3 bands of CAT in the leaves of different Ca2+ treatmnts.There were changes in bands of POD under both conditions.