Air-dry rice seeds (Gui-Chao № 2) were exposed to gamma-rays from a ,60,Co source at different doses. After gamma-irradiation, seeds were germinated. Some enzyme levels (catalase, peroxidase, α-amylase, and phosphatase of the seedlings) were observed during germination. Among the enzymes being studied catalase was extraordinaryly sensitive to and had a positive correlation with the low doses of gamma irradiation, (0, 250, 750, 1500, and 3000 rad, at the dose rate of 750 rad/min).,Catalase activity of the control seedlings was stimulated when the seedlings were oxposed to low concentration (about 30 mM) of exogenous H,2,O,2,.