Objective: To explore the medication compliance for secondary prevention drugs and long-term prognosis of patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) between hospitals in different regions of China. Methods: The Optimal Antiplatelet Therapy for Chinese Patients with Coronary Artery Disease (OPT-CAD) study was a prospective, multi-center and registered study. Patients diagnosed as ACS and underwent PCI in OPT-CAD study were selected. Taking the Yangtze River as the dividing line between the south and the north of China, these patients were divided into two groups according to the hospitals where the patients visited, namely the southerns region group ( n =1 958) and the northerns region group ( n =5 091). In order to reduce selection bias and potential confounding factors, the patients in the two groups were matched by the tendency score, and the patients in the two groups were matched by the 1: 1 nearest match method according to the tendency score. The main endpoint of this study was the major adverse cardiovascular and cerebrovascular events (MACCE) occurring within 5 years after discharge, namely the composite endpoint of cardiac death, myocardial infarction, and/or ischemic stroke. Secondary endpoints were all-cause death, cardiac death, myocardial infarction, ischemic stroke, and type 2, 3, and 5 bleeding events defined by the Academic Research Consortium on Hemorrhage (BARC) within 5 years. The secondary preventive drugs was recorded, including antiplatelet drugs, statins, beta blockers, angiotensin converting enzyme inhibitors/angiotensinⅡreceptor blockers (ACEI/ARB), etc. Before and after the matching, the secondary preventive medication and the incidence of clinical events of the two groups were compared. Results: A total of 7 049 ACS patients, including 1 958 patients in the southern region group and 5 091 patients in the northern region group were enrolled in this study. There were 5 319 males (37.9%), and the aged was (60.7±6.7) years. After propensity score matching, there were 1 324 cases in each group. Before matching, in the northern region group, the proportion of smoking, hypertension and diabetes, previous history (myocardial infarction, PCI and stroke) and family history of coronary heart disease were higher (all P <0.05). The proportion of complex lesions, diffuse lesions, small vessel lesions and thrombotic lesions in the northern region group was higher than that in the southern region group (all P <0.05). Sixty months after discharge, the antiplatelet patterns were quite different between patients in the northern and southern region group ( P <0.001). The proportion of clopidogrel monotherapy in the southern region group was higher than that in the northern region group (9.8% (130/1324) vs. 1.1% (14/1324)), while the proportion of aspirin monotherapy in the northern region group was higher than that in the southern region group (67.4% (893/1324) vs. 46.5% (616/1324)). As for the use of other secondary prophylactic drugs, the proportion of patients in southern region group receiving beta blockers (24.5% (325/1324) vs. 16.8% (222/1324), P <0.001) and ACEI/ARB (19.4% (257/1324) vs. 10.0% (133/1324), P <0.001) was higher than that in northern region group. After matching, the incidence of MACCE (8.4%(111/1 324) vs.6.2% (82/1 324), P =0.030) and BARC 2, 3 and 5 bleeding (6.0% (80/1 324) vs. 4.0% (53/1 324), P =0.020) was higher in patients in northern region group. Conclusions: ACS patients who undergo PCI in northern area hospital is at higher prevalence of comorbidities and complicated coronary artery lesions compared to patients in the southern area hospital, and the drug compliance is worse than that in southern area, and the prognosis is also relatively poor.