Objective To investigate the predictive value of metabolic syndrome in patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI).Methods A total of 660 patients with ACS admited to cardiovascular department,first affiliated hospital of zhengzhou university were enrolled in this study from January 2009 to June 2010.The enrollment criteria were:the stenosis degree were above 75％ in at least one coronary artery by coronary angiography and successful PCI procedure.Exculsion criteria were:liver and renal insufficiency,malignancies and valvular heart diseases.The relevant clinical data and labtory examination were recorded after admission. The patients were followed up by outpatients interview or telephone from March to June 2011 and adverse cardiovascular events were recorded.The patients were divided into MS and non-MS groups,and basic clinical data were compared between two groups.The proportion difference between two groups were tested by chi square. Multivariate logistic regression was established to analyze the factors related to progonosis.The survival ratio was estimated using the Kaplan-Meier method.Statistical significance was established at a P value of less than 0.05.Results ①A total of 606 (91.7％) patients successfully accepted follow-up.Mean follow-up time were ( 14.3 ±1.7 ) months.95 patients experienced adverse cardiovascular events ( 15.7％ ).②There were 393 patients (64.96％ ) satisfied the definition of metabolic syndrome.The patients in MS group were with higher BMI,SBP,DBP,blood glucose and disordered lipid (all P ＜ 0.05 ),with less fale patients (P =0.016),less current somking (P =0.008 ) and with higher platelet (P =0.037 ). The incidence of adverse cardiovascular events in two groups were 17.81％ and 11.79％ ( P ＞ 0.05 ). ③ Multivarite logistic regression revealed that the predictors of adverse cardiovascular events were age [ OR =2.628,95％ confidence interval (CI) 1.395 ～ 4.954,P =0.003 ],New York Heart Association (NYHA) ≥ 3 grade ( OR =2.310,95％ CI 1.095 ～4.870,P =0.028) and left ventricular ejection fraction (LVEF) ( OR =4.328,95％ CI 1.955 ～9.580,P ＜ 0.001 ).However,MS was not related with prognosis ( OR =1.170,95％ CI 0.583 ～ 2.345,P =0.659 ).④The cumulative survival rates of no adverse cardiovascular events in the two groups were no significant difference ( P ＞ 0.05 ).Conclusions MS is a risk factor with coronary heart disease.Howerer,it has no relationship with adverse cardiovascular events in patients with ACS after PCI.