Abstract: Objective To explore portal vein hemodynamic changes and liver regeneration in rats after 70% partial hepatectomy (PH). Methods Rats were randomly subjected into sham operation group and 70%PH group. A 5-12 MHz high-frequency linear transducer was applied to measure the portal vein diameter (PVD) and the maximum portal vein velocity (PVV) before and after operation on day 1, 3, 7, 14. On the corresponding time, liver tissue morphological changes were observed, and the expression level of PCNA was measured, and the liver regeneration rate (LRR) was calculated. Results On day 1 after PH, PCNA began to increase, and hepatocyte vacuolated obviously which squeezed and narrowed the hepatic sinusoid. Meanwhile, PVD started to dilate and PVV decelerated. On day 3 after operation, PCNA peaked and active mitosis resulted in the disorders of hepatic structure. PVD peaked and PVV decelerated to the lowest. Until the 14 d after operation, the cell morphology, lobular structure and PCNA recovered gradually accompany by LRR above 90%. PVD and PVV also almost recovered to levels closed to sham group (P<0.05). Conclusion The hemodynamic parameters PVD, PVV correlated with hepatic pathology changes, mitosis status and regenerated liver volume after PH, which state the potential possibility for ultrasound image study in liver regeneration surveillance.