Objective To explore the influence of heparin sodium on early recovery after lumbar surgery and the risk factors of deep vein thrombosis(DVT)of lower extremities,and build a prediction model for DVT after lumbar surgery based on the risk factors.Methods A total of 276 patients who underwent lumbar surgery and were treated with heparin sodium in The First Affiliated Hospital of Naval Medical University from January 2020 to January 2023 were selected as research objects.Activated partial thromboplastin time(APTT),prothrombin time(PT)and functional indexes of lumbar spine were recorded before and after treatment.DVT of lower extremities was detected by ultrasound during postoperative hospitalization,and then the patients were divided into DVT group and non-DVT group.The clinical data and laboratory indicators of all patients were collected.The risk factors of DVT after lumbar surgery were analyzed by logistic regression analysis.A postoperative DVT risk prediction model based on Logistic regression analysis was constructed and validated.Results APTT and PT after operation were higher than those before operation(P<0.05).The score of Oswestry Disability Index(ODI)3 months after surgery was lower than that before surgery(t=30.661,P<0.05).The incidence of DVT was 14.86%(41/276).Blood transfusion,bed rest≥5 d,proportion of general anesthesia,intraoperative blood loss,body mass index(BMI)and D-dimer level in the DVT group were higher than those in the non-DVT group(P<0.05).Logistic regression analysis showed that intraoperative blood loss,BMI,abnormal D-dimer level,intraoperative blood transfusion,and bed rest≥5 d were all risk factors for DVT after lumbar surgery(P<0.05).logit(P)=9.762+1.425×intraoperative blood loss+1.212×BMI+0.856×intraoperative blood transfusion+1.105×bed rest+1.671×D-dimer.Hosmer-Lemeshow test showed that the model had a high goodness of fit(χ2=4.025,P=0.473).The sensitivity,specificity and area under curve(AUC)of the constructed prediction model for postoperative DVT were 91.80%,70.40%and 0.836(95%CI:0.698-0.948),respectively.Conclusion Heparin sodium can improve blood circulation and lumbar function and prolong clotting time in patients with lumbar surgery.Intraoperative blood loss,BMI,abnormal D-dimer,intraoperative blood transfusion,and bed rest≥5 d are all risk factors for the occurrence of DVT after lumbar surgery.The prediction model based on the above risk factors has high predictive value for the occurrence of DVT after lumbar surgery.