Aim To explore the relationship between the TG/HDLC ratio and in-hospital MACE in acute coronary syndrome (ACS) after percutaneous coronary intervention(PCI). Methods A total of 214 ACS patients receiving primary PCI admitted in our hospital from January 2014 to January 2015 were enrolled in this study. Multivariate analysis was conducted to assess whether TG/HDLC ratio was the independent predictor for in-hospital MACE occurrence.And the subjects were divided into three groups according to TG/HDLC ratio. The differences OR of in-hospital MACE between low TG/HDLC ratio group (n＝66), middle TG/HDLC ratio group (n＝74)and high TG/HDLC ratio group (n＝74) were compared. Results After adjusting for age, smoking, hypertension, diabetes, and severity of angiographic coronary disease by the multivariate Logistic regression model, the LogTG/HDLC ratio was the independent risk factor for in-hospital MACE(OR=6.0,5%CI was 1.90~25.06, P=0.003). ACS patients with the higest tertile of TG/HDLC ratio exhibited multivariable-adjusted OR of 3.27 for in-hospital MACE compared with ACS patients with the lowest quartile of TG/HDLC ratio. Conclusion The TG/HDLC ratio is a powerful independent predictor of MACE.