With the development of water stress, the activities of superoxide dismutase (SOD) and malondialdehyde(MDA) content increased, the calmodulin(CaM ) levels declined. The SOD activities and MDA content declined to the control level, while the CaM content greatly increased higher than control levels 4 days after rewartering the flaccid seedlings. The results showed that SOD might be not regulated by CaM. The experiment also contained a study on SOD activity assay and the calculating methods.