Objective To explore the relationship between methylene tetrahydrofolate reductase(MTHFR)C677T gene polymorphism and serum homocysteine(Hcy)levels with postoperative restenosis in patients with lower limb arteriosclerosis obliterans(ASO)after intervention.Methods A total of 92 patients with lower limb ASO treated in Wenzhou Central Hospital from January 2021 to July 2022 were divided into non-restenosis group and restenosis group according to whether patients with postoperative restenosis.General and surgical data from all patients were collected,and preoperative neutrophils,lymphocytes,platelets,fibrinogen,D-dimer,C-reactive protein,low-density lipoprotein,homocysteine,MTHFR C677T gene polymorphism,etc were tested.x2 test and Logistic regression analysis were used to compare the relationship between lower limb ASO postoperative restenosis after intervention and MTHFR C677T gene polymorphism and serum Hey.A risk scoring system was built to predict postoperative restenosis after intervention and evaluate its effectiveness.Results There were significant differences(P＜0.05)between the two groups in terms of lesion location,stent placement,stent length,serum Hcy,and MTHFR C677T gene polymorphism.Multivariate Logistic regression analysis showed that MTHFR C677T TT type,serum Hey 17.15μmol/L,lesion location in the femoral artery,and no stent placement were independent risk factors for postoperative restenosis in lower limb ASO patients(P＜0.05).The area under the curve(AUC)of receiver operating characteristic curve of the risk scoring system constructed based on independent risk factors was 0.818(95％CI:0.731-0.905),which was significantly higher than those other independent risk factors and had high efficacy.Conclusion The MTHFR C677T gene polymorphism and serum Hcy are closely related to postoperative restenosis in lower limb ASO patients.A risk scoring system based on MTHFR C677T gene polymorphism,serum Hcy,lesion location,and stent placement can help predict the occurrence of restenosis in lower limb ASO patients.