In order to study the mechanism of decreased blood pressure caused by an acute increase in biliary tract pressure, we observed house rabbit model of self-made caecus for changes in cardiovascular function when biliary tract pressure was increased. It was found that both the blood pressure and cardiac output evidently decreased (P<0.05) parallelly, and the systolic pressure decreased more markedly than diastolic pressure. At the same time there was fluctuation in heart rate and in central venous pressure; but there was no significant difference between them (P>0.05), suggesting that in the absence of infective agents, the increased biliary tract pressure can bring about a decrease in cardiac output, which is an important factor contributing to an early blood pressure decrease in acute cholangitis of severe type (ACST).