Background: Acute coronary syndrome (ACS) is a common disease in the elderly, and the incidence of myocardial infarction and cardiac death can be increased by 2-4 times if diabetes mellitus is combined, and the incidence of multiple coronary lesions, distal lesions and the stenosis index and calcification index of affected coronary arteries are significantly higher than those of patients with normal glucose tolerance. Percutaneous transluminal coronary angioplasty (PTCA) + stenting via the radial artery is the conventional route of interventional treatment for acute coronary syndrome, but it is difficult to perform. With the development of medical technology, the transradial route for cardiac catheterization and treatment has been widely used. In this study, we observed the results and postoperative complications in elderly patients with ACS combined with type 2 diabetes mellitus (2Diabetes, type 2 DM) treated by this route. Methods Fifty-eight patients were divided into elderly patients with ACS combined with diabetes mellitus who underwent percutaneous transluminal coronary angioplasty (PCI) (group A, 34 patients) and elderly patients with ACS without diabetes mellitus (group B, 24 patients) to observe the success rate and postoperative complications. There was no significant difference in the success rate of PCI between the two groups; the number of patients with lesions in single, double, triple and left main branches was higher in group A than in group B with diabetes mellitus. There was a statistically significant difference in the number and location of lesions between the two groups (P=0.0012). There was a significant difference between the two groups in terms of type of vascular lesions (P=0.005). The incidence of local hematoma (3 cases in group A, 1 case in group B), pseudoaneurysm (1 case in group A, none in group B), swelling of the operated limb (1 case in group A, 2 cases in group B), and arteriovenous fistula (none in group A, 1 case in group B) were different but not statistically significant, and there were significant statistical differences; there was no distal limb ischemia in both groups. Conclusion The coronary artery lesions in elderly patients with ACS with type 2 DM were more severe than those in the non-diabetic group, and PTCA via the radial artery route was less painful and less complications in elderly diabetic patients with ACS, which was easily accepted by patients, but attention should still be paid to the tortuosity of the unnamed artery.