Alteration of the activities and distribution of the enzymes on liver cell surface in biliary obstruction was discussed. Biliary obstruction of rat elevated alkaline phosphatase activity on the bile canalicular surface area and the other surface area. The rise of the activity was observed on the bile canalicular surface and then the intercellular and sinusoidal surface. At the time of the elevation of bile canalicular alkaline phosphatase activity, the activity in the serum rose and the biliary form of the enzyme was found in the serum. These finding suggest the disorder of the tight junction, which lead to the loss of the polarization on the liver cell surface as well as the leakage of biliary component in the blood. Biliary obstruction also induced the decrease of ATPase activities on the bile canalicular surface. However ATPase activities on the intercellular and sinusoidal surface remained unchanged. This finding also suggests the loss of the polarity on the liver cell surface.