Abstract: The serum levels of Alpha-Fetoprotein (AFP)and Alpha-L-Fucosidase (AFU) were determined in 240 patients with Primary Hepatocellular Carcinoma(PHC),91 patients with digestive tract cancers,41 patients with other malignant neoplasms and 60 healthy subjects.The result showed that the serum AFU activity in patients with PHC ( 241 .9士112.5) was significantly higher than in control (116.1士28.0) and other patients(P<0.O1).AFU sensitivity and specificity were 69.6%and 90.1%,respectively.There was not significant correlatively of the AFU activity and the level of AFP in the serum.Throuth combination of AFU and AFP assay,the diagniostic positively in PHC could be raised to 89.6%.Marked decreases or increase of AFU levels followed patient's condition that was improved or got worse after surgical resection or chemotherapy .In consequence,the method of determination of serum AFU activity was clinically valuable in the diagnosis,observation of treatment efect in PHC.