Objective: To explore serum levels of lipoprotein associated phospholipase A2 ( LP-PLA2) in patients with acute coronary syndrome (ACS) who is smoking, to further clarify the impact of smoking on LP-PLA2 and the relationship with coronary artery disease (CAD). Methods: A total of 170 patients who received coronary angiography (CAG) because of chest pain in our hospital from 2015-01 to 2015-12 were enrolled. According to CAG results and smoking history, the patients were divided into 2 groups:Control group, n=70 healthy subjects including 2 subgroups as Smoking control subgroup, n=31 and Non-smoking control subgroup, n=39; ACS group, n=100 patients including 2 subgroups as Smoking ACS and Non-smoking ACS subgroups, n=50 in each subgroup. Blood levels of LP-PLA2 and C-reactive protein (CRP) were detected and compared among different groups. Results: Serum levels of LP-PLA2 in Smoking control subgroup was higher than Non-smoking control subgroup, P=0.018; LP-PLA2 level in Smoking ACS subgroup was higher than Non-smoking ACS subgroup,P=0.027; LP-PLA2 level in ACS group was higher than Control group,P=0.000. Serum levels of LP-PLA2 was positively related to CRP (r=0.724,P<0.01). Conclusion: Blood levels of LP-PLA2 and CRP were increased in ACS patients suggesting both of them might be involved in CAD occurrence; LP-PLA2 level was even higher in smokers implying this is could be one of the reasons for smokers were more likely to suffer from CAD and aggravate CAD progress.