Abstract： Objective To investigate the difference of endothelial lipase ( EL) expression in in-stent restenosis(ISR)patients and its clinical significance. Methods A retrospective study was performed on 48 cases of patients who were admitted and underwent coronary angiography ( CAG) and drug-eluting stents(DES)from January 2014 to December 2017. According to the results of CAG review 6 months to 4 years after the first stent placement,patients were divided into the stent restenosis group(20 cases)and the non-stent restenosis group(28 cases).Fasting blood glucose,triglyceride,total cholesterol,LDL-C,HDL-C and serum EL levels were measured in the two groups.Multivariate logistic regression was used to analyze ISR risk factors.ROC curve was used to evaluate the clinical recognition ability of EL in ISR patients. Results The proportion of patients with type 2 diabetes and smoking in the stent restenosis group was higher than that in the non-stent restenosis group(P<0.05).LDL-C and EL in the stent restenosis group were higher than those in the non-stent restenosis group(P<0.05).The total length of stent implantation in the restenosis group was greater than that in the non-restenosis group( P<0.05). Multivariate logistic re-gression analysis showed that type 2 diabetes mellitus,total stent length and EL were all risk factors for ISR. ROC curve showed that EL had certain clinical recognition ability for ISR [ AUC =0.757,95% CI (0.645 ~ 0.899),P<0.05]. Conclusion Type 2 diabetes,the total length of stent placement and EL are independent risk factors for ISR.EL is closely related to ISR,which has a better predictive ability for ISR after DES implantation.