To study the relationship between the activity of endogenous β-glucuronidase (β-G) in hepatic tissue and the formation of bilirubin stone. We assessed the β-G activity in hepatic tissue of 44 cases of bilirubin stone, 8 cases of cholesterol stone and 25 cases of liver injury by using immunohistochemistry. Results: The cell percentage of β-G positive reaction in bilirubin stone group (49.2%±4.6%) was significantly higher than those in cholesterol stone group (32.5%±3.8%) and liver injury group (27.8%±4.2%), Ｐ＜0.05. There was no relationship between cell percentage of β-G positive reaction and age, patient history, size of stone. Conclusions: The activity of endogenous β-G is closely related to the formation of bilirubin stone. The difference of activity between individuals is possibly the intrinsic factor which may influence the formation of bilirubin stone.