Objective To investigate the risk factors of portal vein thrombosis (PVT) in patients with liver cirrhosis.Methods From January 2009 to December 2011,the data of 294 hospitalized patients diagnosed as liver cirrhosis were retrospectively analyzed.PVT was diagnosed according to multislices spiral computed tomography or color doppler ultrasonography.Fifty-five patients with liver cirrhosis and PVT were in PVT group,239 patients with liver cirrhosis however no PVT were in non-PVT group.Age,gender,etiology of cirrhosis,Child-Pugh grading and score,blood routine examination,blood chemistries,blood coagulation function,D-dimer,main portal vein (MPV) internal diameter,portal vein velocity (PVV) and thickness of spleen were recorded and analyzed.The measurement data were analyzed by t test.Unconditional Logistic regression model was performed to screen corresponding risk factors.Area under curve (AUC) was calculated according to receiver operator characteristic (ROC) curve to evaluate the diagnostic value of each index.Results The results of white blood cell,hemoglobin,total bilirubin,creatinine,serum natrium,prothrombin time,activated partial prothrombin time,fibrinogen and international normalized ratio of PVT group were similar with those of non-PVT group and there were no statistically significant differences (all P＞ 0.05).Compared with those of non-PVT group,the differences in platelet count,albumin level,the level of D-dimer,MPV internal diameter,PVV,spleen thickness,and Child Pugh score of PVT group were statistically significant ((82.55 ± 23.04) × 109/L vs (99.66±20.23)×109/L(t=-0.308,P=0.022),(30.53±2.32) g/L vs (33.36±3.62) g/L(t=-2.117,P=0.036),(1.00±0.22) mg/L vs (0.77±0.15) mg/L(t=7.557,P=0.003),(15.11± 1.32) mmvs (13.40±1.43) mm(t=8.013,P=0.014),(13.51±1.51) cm/s vs (15.16±1.60) cm/s (t=-6.979,P=0.036),(59.35±5.45) mm vs (54.64±5.92) mm(t=1.9555,P=0.043),(11.73± 2.01) scores vs (8.18 ± 3.05) scores (t =6.225,P =0.006)).The results of unconditional Logistic regression model analysis indicated that D-dimer,Child-Pugh score,MPV and PVV were independent risk factors of PVT in patients with liver cirrhosis (OR=13.420,10.237,8.534,0.151; P=0.001,0.014,0.019,0.025).ROC curve analysis indicated that the AUC of D-dimer,Child-Pugh score,MPV and PVV was 0.868,0.823,0.810 and 0.756,respectively.The predicate value was D-dimer＞ Child-Pugh score＞ MPV＞ PVV.Conclusion D-dimmer,Child-Pugh score,MPV and PVV are independent risk factors of PVT in paitients with liver cirrhosis.