Objective To explore adaptive condition of preparation of animal model and afford reliable and stable model animal for further research on clinical diagnosis and treatment of cavernous transformation of portal vein (CTPV) by establishment of animal model by partial portal vein stenosis. Methods According to different straight blunttip needles used, 80 healthy Sprague-Dawley rats were randomly averagely divided into 4 groups: sham operation group, gauge 19 (19G) group, gauge 21 (21G) group and gauge 23 (23G) group. Six weeks after model making, pressure measurement and angiography of portal vein and pathological examination of portal vein and its surrounding tissues were used to evaluate portal hypertension and CTPV. Results Six weeks after model making no rat died in sham operation group, while the numbers of died rats in 19G group, 21G group and 23G group were 2, 4 and 16, respectively. No portal hypertension was displayed in sham operation group and 19G group 6 weeks after model making. Portography showed that the portal vein seemed smooth without variceal and dilatation in sham operation group and 19G group. Pathological examination demonstrated that the portal vein walls were not enlarged, endothelial cells were smooth. The smooth muscles of middle membrane were not thickened and adventitia was intact. Portal pressure increased and CTPV formed in 21G group and 23G group 6 weeks after model making. Portography showed that collateral circulation formed around portal vein in 21G group and 23G group. The vessel lumens with different size and irregular shapes were displayed by pathological examination. Within the narrow fibrous septum between there were the lumens the fat cells, scattered lymphocytes and mast cells, etc. The portal vein walls were enlarged notably, endothelial cells were damaged, the smooth muscle of middle membrane were thickened, thrombosis were formed. Conclusion Establishment of CTPV animal models by partial portal vein stenosis is a reliable method. 21G blund-tip needles fits well in the preparation of CTPV, which is reliable and stable with lower mortality.