Objective:To compare the liver fibrosis induced by microcapsules transplantation via portal vein(group V) and hepatic artery(group A). Methods:Thirty dogs in this experiment were randomly divided into two groups:group A(microcapsules implanted into hepatic artery by hepatic artery catheterization) and group V(microcapsules implanted into portal vein by percutaneous transhepatic approach guided by ultrasound). And three sub groups of unequal microcapsules(8 000/Kg,16 000/Kg and 32 000/Kg) were given to both group A and group V respectively, each to five dogs. The main serum liver fibrosis indexe type Ⅳ collagen(CIV) was measured before and after the transplantation. Samples of the livers were examined pathologically before and after the operation. Results:In group V, C IV elevated gradually, and the values were significantly different from the pretransplant’s(P < 0.01). In group A, CIV showed no significant difference before and after transplantation(P > 0.05). The difference between group Vn and An was significant(P < 0.01). In group V3, some pathogenic changes indicating liver fibrosis were found in the hepatic sections stained with HE at 12 weeks’ post-transplant, but none in group A, and the structure of lobule remained normal at 12 weeks’ post-transplant in the latter. Conclusion:When the quantity of microcapsules was 32 000/kg, changes of serum liver fibrosis indexes and pathological liver such as liver fibrosis could be found in group V at 12 weeks’ after transplantation, while microcapsules transplantation via hepatic artery can avoid the damage of liver. Compared with via portal vein, via hepatic artery microcapsules transplantation avoided risks of liver damage in some degree, and thus can be regarded as a relatively safe and simple approach of transplantation of islet cells into the liver.