AIM: To study the dynamic changes of free radicals and antioxidative system of prostate in rats with short-term diabetes. METHODS: 48 Wistar male rats were divided into 6 groups at random (8 rats in each group). One group were injected(ip) with sodium citrate buffer to be the control group, the other 5 groups were injected (ip) with steptozocin(STZ) 60mg/kg body weight which were called diabetes group. Rats were killed after 1, 3, 5, 7 and 14 days; superoxide dismutase(SOD), malondialdehyde(MDA), glutathione(GST), glutathione s-transferase(GST), glutathione peroxidase(GSH-px), nitric oxide (NO) and nitric oxide synthase(NOS) of prostate were examined. RESULTS: The levels of MDA, GSH-px and NO in prostate homogenate of diabetes group were higher evidently as compared with control levels. The activities of SOD, GST, NOS and the levels of GSH in prostate homogenate were increased obviously after injection of STZ with control levels, then returned near to control values. CONCLUSION: The evidences mentioned above indicate that high-level of free radicals and decrease in antioxidative system rendere the prostate cells to be in oxidative stress.