Abstract: Objective To explore the value of combined detection of lipoprotein-related phospholipase A2（Lp-PLA2）, retinol binding protein （RBP）, serum homocysteine （Hcy）, and plasma oxidized low-density lipoprotein （ox-LDL） in the diagnosis and prognosis of acute coronary syndrome （ACS） patients under 50 years old. Methods 90 ACS patients diagnosed by coronary angiography from January 2018 to December 2019 were selected as the research objects, including 40 acute myocardial infarction （AMI） patients and 50 unstable angina pectoris （UAP） patients, and 80 volunteers who had physical examination in our hospital at the same time were selected as the control group. We collected and recorded the clinical data and biochemical indicators, left ventricular ejection fraction （LVEF） and Gensini scores of all study subjects. The pearson correlation analysis was used between Gensini score and Lp-PLA2, RBP, Hcy, ox-LDL levels in ACS patients, the multivariate logistic analysis was used to analyze the risk factors of major adverse cardiovascular events （MACE）, the receiver operating curve （ROC） was used to analyze the value of Lp-PLA2, RBP, Hcy and ox-LDL in the prognosis of ACS, and consistency test was conducted. Results The LVEF of the AMI group was significantly lower than that of the UAP group and the control group, the Gensini score, the levels of Lp-PLA2, RBP, Hcy, and ox-LDL were significantly higher than that of the UAP group and the control group（P<0.05）. Pearson correlation analysis results showed that the levels of Lp-PLA2, RBP, Hcy and ox-LDL in ACS patients were positively correlated with the Gensini score. Gensini score, Lp-PLA2, RBP, Hcy and ox-LDL are independent risk factors for MACE （P<0.05）. ROC curve analysis showed that the combination of Lp-PLA2, RBP, Hcy and ox-LDL had a good diagnostic value for the prognosis of ACS patients （area under curve 0.919, sensitivity 93.9%, specificity 92.4%）. The prediction model had high consistency with the actual value. Conclusions The levels of Lp-PLA2, RBP, Hcy and ox-LDL could be used as biochemical markers for the diagnosis of coronary artery disease, and the combination of them had relatively accurate predictive value for the prognosis of ACS patients.