Background Treatment of coronary in-stent restenosis (ISR) remains challenging in contemporary clinical applications. Drug-coated balloon (DCB) angioplasty offers an effective treatment for ISR. Shenqi is a novel iopromide-based paclitaxel-coated balloon and its clinical safety, effectiveness and angiographic efficacy in patients with ISR have not been investigated. Methods A total of 216 subjects with the first occurrence of ISR at 11 investigational sites in China were randomly allocated in a 1:1 fashion to treatment with DCB SeQuent Please or Shenqi. Clinical follow-up was planned at 1, 6, 9 and 12 months, and angiographic follow-up was planned at 9 months. The study was powered for the primary endpoint of 9-month in-segment late loss. Results At 9-month follow-up, the in-segment late loss was 0.29 +/- 0.43 mm with Shenqi versus 0.30 +/- 0.46 mm with SeQuent Please, and the one-sided 97.5% upper confidence limit of the difference was 0.14 mm, achieving noninferiority of Shenqi compared with SeQuent Please (P = 0.002). In total, 12 patients developed target lesion failure (TLF) in the Shenqi group compared with 16 patients in the SeQuent Please group (10.91% versus 15.09%; P = 0.42) within 1 year. TLF was mainly driven by target lesion revascularization (9.09%) followed by target vessel-related myocardial infarction (1.82%) and cardiovascular death (0.91%) in the Shenqi group. Conclusions Shenqi DCB was noninferior to SeQuent Please DCB for the primary endpoint of 9-month in-segment late loss. Shenqi DCB may become an attractive alternative treatment for patients with coronary ISR, withholding the need for additional stent implantation.