Objective To investigate the risk factors of early thromboembolism after pancreaticoduodenectomy with vein reconstruction.Methods The results of bedside ultrasonography and clinical data of 90 patients from Ruijin Hospital,Shanghai Jiao Tong University School of Medicine who underwent pancreaticoduodenectomy with vein reconstruction within 7 days after operation between Janurary 2018 and September 2021 were analyzed retrospectively.According to the results of bedside ultrasound examination of the patency of portal vein,the postoperative patients were divided into portal vein pa-tency group and portal vein embolization group.The hemodynamic differences of bedside ultrasound and the influencing factors of postoperative portal vein thromboembolism were compared.Results Among 90 patients underwent bedside ultra-sound,8 patients had portal vein thromboembolism after pancreaticoduodenectomy with vein reconstruction,and the inci-dence rate was 8.89％.Bedside ultrasound showed that the velocity and flow of portal vein in patients with portal vein thromboembolism decreased significantly(P＜0.0O1).Among the perioperative related risk factors,there was a statistically significant difference in the smoking history and alcohol abuse history between the portal vein patency group and portal vein thromboembolism group.Further,previous smoking history was an independent risk factor for portal vein thromboem-bolism(P=0.003).The outcomes showed that the pancreaticoduodenectomy with vein reconstruction was safe and feasible,however early portal vein thromboembolism with severe complications indicated a poor prognosis.Conclusions The history of smoking and alcohol abuse are the high risk factors of portal vein thromboembolism after pancreaticoduodenectomy with vein reconstruction,which should be prevented by preoperative education.Bedside ultrasound can effectively and safely evaluate the patency of portal vein after pancreaticoduodenectomy with vein reconstruction,which contributes to early clini-cal intervention.