Aim To explore the role of inflammation in acute coronary syndrome (ACS) and the mechanism by which statin treat ACS. Methods The serum high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) levels were measured in 50 patients with ACS, including 30 patients with unstable angina (UA) and 20 patients with acute myocardial infarction (AMI), 34 patients with stable angina (SA) and 30 controls. 30 patients in ACS group were randomly selected and assigned to the simvastatin group (n=15) and the routine group (n=15). The simvastatin group was given simvastatin 20 mg/d and the routine group took placebo expect routine treatment (including nitrate, aspirin , β-blocker and ACEI ). After a three-week follow-up, serum hs-CRP, IL-6 levels and serum lipids concentrations were measured again. Results Both serum IL-6 and hs-CRP levels were significantly higher in ACS group than in SA and normal control group(p<0.001). After three-week treatment with simvastatin, serum IL-6, hs-CRP, total cholesterol (TC) and low density lipoprotein cholesterol (LDLC) levels decreased significantly in the simvastatin group (p<0.001), but not in the routine group. The rates of decrease of IL-6 and hs-CRP was significantly different between simvastatin group and routine group (p<0.05). No relationship was observed between the values of decrease of serum IL-6 or hs-CRP and serum lipids levels. The serum hs-CRP level showed significant correlation with coronary heart disease (CHD) in both univariate regression pattern and multivariate regression pattern (p<0.05) . Conclusions Inflammation plays an important role in the initiation of ACS. Assaying serum IL-6 and hs-CRP levels may be able to help to definite the diagnosis of ACS. Simvastatin possess anti-inflammatory effect which independent of its lipid lowering action, and the anti-inflammatory effect of simvastatin might play an important role in the early treatment of ACS.