Objective: To study the feasibility and reliability of ultrasound monitoring of hepatic portal vein blood flow (Qpv), hepatic venous blood flow (Qhv) and the ratio of the two (Qpv/Qhv) during the process of liver cancer induction in SD rats, and to preliminary study Qpv/Qhv The correlation between the change of value and the pathological process of liver cirrhosis and liver cancer. Methods: During the process of SD rats being induced to liver cancer, regular ultrasound examinations of the liver of the rats including color blood flow imaging, pulsed Doppler imaging, and measurement of portal vein trunk (PV) and hepatic vein (HV) blood flow parameters , And calculate the ratio of portal venous blood flow to hepatic venous blood flow (Qpv/Qhv) until the rat is induced to liver cancer. Results: As the degree of liver cirrhosis deepened, the diameter of the portal vein trunk increased gradually (P<0.05). The average flow velocity of the main portal vein in the liver cancer stage and cirrhosis stage was lower than the normal stage (P<0.05), and the portal vein blood flow was higher than the normal stage. The blood flow of the hepatic vein in the normal phase is significantly greater than that in the cirrhosis and liver cancer phases. The ratio of portal venous blood flow to hepatic venous blood flow (Qpv/Qhv) in the normal phase was significantly lower than that in the cirrhosis and liver cancer phases, but there was no significant difference in Qpv/Qhv between the cirrhosis and liver cancer phases. Conclusion: Non-invasive ultrasound detection of blood flow can be used as a reliable method to monitor liver hemodynamic changes in SD rat models of liver cirrhosis and liver cancer. The change of Qpv/Qhv value has a certain correlation with the pathological process of liver cirrhosis and liver cancer.