Objective To explore the influence of enoxaparin anticoagulation following percutaneous coronary intervention (PCI) on clinical events among patients with different ages. Methods A total of 700 patients without high risk of stent thrombosis complications such as no-reflow and coronary artery dissection, who had undergone PCI in the Cardiology Department of Changhai Hospital and Suzhou Municipal Hospital from 2010 to 2014, were recruited in the present study. The patients were randomly assigned to anticoagulation therapy (enoxaparin) group or non-anticoagulantion group. The in-hospital bleeding events and main adverse cardiac and cerebral vascular events (MACCEs) in 1 year were compared between patients of the two groups of three different age periods: middle age patients (< 60 years old), old patients (60-74 years old) and advanced age patients (≥75 years old). Results There were no significant differences in the incidences of in-hospital minor bleeding between anticoagulation group and non-anticoagulation group in the middle age patients (21.5% vs 18.8%). Compared with non-anticoagulation group, in-hospital minor bleeding was significantly increased in anticoagulation groups in old patients(36.4% vs 23.5%, P <0.05)and advanced age patients (46.7% vs 22.4%, P <0.05). There were no significant differences in the incidences of in-hospital deep venous thrombosis (DVT) between anticoagulation groups and non-anticoagulation groups among various ages. The average hospital stay was significantly increased in anticoagulation group than in the non-anticoagulation group in old patients and advanced age patients(P <0.05). There were no significant differences in incidences of MACCEs in 1 year between the patients of the two groups of different ages (4.1% vs 4.3% in middle age patients, 7.3% vs 6.6% in old patients, and 11.7% vs 10.3% in advanced age patients, respectively). Kaplan-Meier curves showed that the in-hospital bleeding was not associated with MACCEs in one year. Conclusion Giving no anticoagulation does not increase MACCEs or in-hospital DVT in patients without high risk for stent thrombosis complications following PCI, and it can also reduce the in-hospital minor bleeding in old and advanced age patients.