Purpose:To study the relationship between the glitathione S transferase and bladder cancer. Methods: The glutathione Stransferase GST) activity has been studied in serum of 58 bladder cancer patients,80 urinary non-tumor patients and 40 normal controls as well as in 27 cancer tissues,adjacent normal tissues and 13 normal bladder tissues.The grade and stage are classified according to the pathology. Results:The GST activity in serum of bladder cancer patients is much higher than that of non-tumor patients and normal control (P＜0.001＝. There is no difference of GST activity between non-tumor patients and normal controls. The GST activity in cancer tissues is significantly increased as compared with adjacent mormal tissues and normal controls (P＜0.001＝.There is no difference of GST activity between adjacent normal tissues and normal tissues. Among groups of different grade, the GST activity had no statistically differences either in serum or in cancer tissues.But the enzyme activity is increased in high stage (P＜0.05. Conclusions:The results revealed a positive relation between the GST activity and the development of the bladder cancer as well as the malignant degree.