Aim To investigate the influence of diabetes on the long-term prognosis in patients with coronary heart disease (CHD) treated by percutaneous coronary intervention (PCI). Methods A total of 2367 consecutive patients with CHD treated by PCI were selected. According to whether there was diabetes, the patients were divided into two groups:diabetes group (n＝719) and non-diabetes group (n＝1648). The influence of diabetes on the long-term prognosis of patients with CHD after PCI was studied by the COX regression analysis. Results Compared with the non-diabetes group, the rate of male patients and level of high density lipoprotein cholesterol (HDLC) were lower, the levels of triglyceride and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were higher, the proportions of old myocardial infarction (OMI), cardiac dysfunction, hypertension, renal dysfunction and cerebral apoplexy were higher in the diabetes group. The proportion of coronary three-vessel lesion, chronic occlusion ratio and Gensini score were higher, average number of stents was more and the average length of stent was longer in the diabetes group. Postoperative follow-up showed that there was no significant difference on all-cause mortality, major adverse cardiovascular event (MACE), cardiac death, nonfatal myocardial infarction and unplanned repeat revascularization between the two groups. Multivariate COX regression analysis showed that there was no significant correlation between diabetes and long-term prognosis of patients with PCI. Conclusions PCI patients with diabetes have special clinical characteristics, but the long-term prognosis is not significantly adverse.