Objective To investigate the clinical value of drug-coated balloon(DCB)in the treatment of in-stent restenosis(ISR).Methods A total of 80 patients with ISR admitted to the Department of Cardiovasology of Nantong Haimen People's Hospital from January 2018 to October 2021 were enrolled and assigned to observation group(n=40)or control group(n=40)according to the random number table method.DCB was applied in the observation group and drug-eluting stent(DES)was used in the control group.The lumen diameter and stenosis rate of target vessels before surgery and immediately after surgery,intraoperative incidence of coronary artery dissection,and the occurrence of major adverse cardiovascular events(MACEs)and ISR within 12 months after surgery were compared between the two groups.Results There were no significant differences in clinical data between the two groups(P>0.05).There were no significant differences in the lumen diameter or stenosis rate of target vessels before treatment between the two groups.After treatment,the lumen diameter and the stenosis rate of target vessels were significantly improved in both groups,and the improvement in the observation group was superior to the control group(P<0.05).But there was no significant difference in the incidence of coronary artery dissection between the two groups.The lumen diameter of the target vessels by re-examination coronary angiography in the observation group was significantly higher than that in the control group,while the stenosis rate of the re-examination target lesion and the incidence of recurrent ISR in the observation group were significantly lower than those in the control group(P<0.05).The total incidence of MACEs in the observation group was significantly lower than that in the control group,and the event-free survival time in the observation group was significantly longer than that in the control group(P<0.05).Conclusion DCB can improve the treatment effect of ISR and reduce long-term adverse events.It has high clinical safety and high clinical application value.