Abstract： Objective To analyze the risk factors of portal vein and splenic venous thrombosis in patients with acute pancreatitis(AP).Method The Clinical data of 309 patients with AP admitted to Tianjin Nankai Hospital/Tianjin Integrated Traditional Chinese and Western Medicine Hospital from February 2018 to March 2023 were collected.All patients were followed up for 3 months after treatment,and patients with portal vein and splenic venous thrombosis were included in the thrombosis group(n=103).According to the gender and age of the thrombosis group patients,a propensity matching method was used to select 206 patients with AP who did not develop venous thrombosis in a 1∶2 ratio and were included in the non-thrombosis group(n=206).The general information,laboratory indicators within 48 hours after admission[prothrombin time(PT),platelet count(PLT),C-reactive protein(CRP),D-dimer(D-D),neutrophil percentage(NEUT)],and related medical history of two groups of patients were compared.The influencing factors of AP complicated with venous thrombosis was analyzed,and the diagnostic efficacy of individual and combined application of each influencing factor on AP complicated with venous thrombosis through the receiver operator characteristic(ROC)curve and its area under the curve(AUC)were evaluated.Result The results of univariate analysis showed that the PT of thrombosis group patients was shorter than that of non-thrombosis group patients,the levels of CRP,D-D,NEUT,and the proportion of patients with a history of esophageal and gastric varices were higher than those of non-thrombosis group patients,the differences were statistically significant(P<0.05).The results of multivariate analysis showed that higher CRP level,higher D-D level,higher NEUT,and a history of esophageal and gastric varices were all risk factors for AP complicated with venous thrombosis(P<0.05);slower PT is a protective factor for AP complicated with venous thrombosis(P<0.05).ROC curve analysis results showed,CRP≥19.785 mg/L,NEUT≥10.485×109/L,D-D≥511.800 μg/L,presence of a history of esophageal and gastric varices,and PT<11.395 s can indicate the possibility of AP complicated with venous thrombosis(P<0.05).CRP and NEUT have moderate predictive value for AP complicated with venous thrombosis(P<0.05),while D-D,presence of esophageal and gastric varices,and PT have lower predictive value for AP complicated with venous thrombosis(P<0.05).The combined application of various influencing factors has higher predictive value for AP complicated with venous thrombosis(P<0.05).Conclusion The higher CRP level,higher D-D level,higher NEUT,and a history of esophageal and gastric varices were all risk factors for AP complicated with venous thrombosis;slower PT is a protective factor for AP complicated with venous thrombosis.Improving the relevant examinations for AP patients based on the above risk factors and conducting specialized prevention and treatment is an important foundation for improving the level of prevention and treatment of portal vein and splenic vein thrombosis.