Aim To evaluate the impact of atherogenic index of plasma (AIP) on prognosis in patients with premature acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI). Methods A total of 208 premature ACS patients (male≤55 years old, female≤65 years old ) with PCI were studied. According to the cutpoint of AIP at 0.06, the patients were classified as atherogenic phenom group (n=155) and non-atherogenic phenom group (n=53). The patients were followed-up for 1 year. The basic clinical characteristics, incidences of mortality and major adverse cardiovascular and cerebravascular events (MACCE) were compared between two groups. Results Atherogenic phenom group had higher mortality, higher rate of MACCE than those in non-atherogenic phenom group (11.0% vs 1.9%, P＜0.05; 24.5% vs 11.3%, P＜0.05, respectively). Multiple factor Logistic analysis revealed that AIP was independently associated with MACCE among patients with premature ACS at 1 year after PCI(OR=2.9,5%CI:1.426~3.209, P<0.05). Multiple Cox proportional hazard analysis showed that AIP was an independent predictor for all cause death among patients with premature ACS at 1 year after PCI (HR=1.7,5%CI:1.137~2.879, P<0.05). Conclusion AIP has a certain predictive value for all-cause death and MACCE after PCI in patients with premature ACS.