OBJECTIVE： To observe the effects of nicorandil on vascular endothelial function and angina pectoris recurrence in patients with unstable angina pectoris after percutaneous coronary intervention （PCI）. METHODS： Totally 195 patients with unstable angina pectoris were collected from Sichuan Provincial People’s Hospital during Jan. 2016-Mar. 2018， and then divided into control group （97 cases） and observation group （98 cases） according to random number table. Both groups received PCI， and then given basic treatment as Enoxaparin sodium injection， Isosorbide mononitrate sustained-release tablets， Aspirin enteric-coated tablets， Clopidogrel sulfate tablets and Atorvastatin calcium tablets after PCI. Observation group additional received Nicorandil tablet 5 mg， tid， on the basis of control group. Both groups were treated for 6 months. The levels of vascular endothelial function related indexes （FMD， ET-1， NO）， myocardial injury markers （cTnⅠ， CK-MB） and inflammatory factors （hs-CRP） were observed before and after PCI. The recurrent angina pectoris， the occurrence of MACE and ADR were recorded. RESULTS： 6 patients of control group and 4 patients of observation group withdrew from the study. One day before operation， there was no significant difference in the levels of vascular endothelial function， myocardial injury markers or inflammatory factors between 2 groups （P＞0.05）. One day after operation， the levels of FMD and NO in both groups decreased significantly， while the levels of ET-1， cTnⅠ and CK-MB increased significantly （P＜0.05）. The levels of FMD and NO were increased significantly in the 1st and 6th months after surgery， and the observation group was significantly higher than the control group； the levels of ET-1， cTnⅠ， CK-MB and hs-CRP were decreased significantly， and the observation group was significantly lower than the control group （P＜0.05）. The incidence and times of recurrent angina pectoris， duration， the proportion of grade Ⅲ angina pectoris and total incidence of MACE in observation group were significantly lower， less or shorter than control group （P＜0.05）. There was no statistical significance in total incidence of ADR between 2 groups （P＞0.05）. CONCLUSIONS： Additional use of nicorandil can improve vascular endothelial function， relieve the myocardial injury and inflammatory response， reduce the occurrence of recurrent angina pectoris and MACE after PCI and doesn’t influence the safety of routine treatment.