Aim To investigate the changes of serum heat shock protein 70(HSP70)levels and its related factors in patients with coronary heart disease(CHD).Methods 66 patients with CHD and 21 healthy controls(non-CHD group)were enrolled in this study.66 patients with CHD were divided into two groups:acute coronary syndrome group(composed of acute myocardial infarction group(AMI,n=23)and unstable angina pectoris group(UAP,n=23)),stable angina pectoris group(SAP,n=20).Serum HSP70 levels were determined by ELISA.Meanwhile high sensitive C-reactive protein(hs-CRP),fasting blood sugar(FBS),total cholesterol(TC),triglyceride(TG),low density lipoprotein cholesterol(LDLC),high density lipoprotein cholesterol(HDLC),and peripheral white blood cell(WBC)count were measured.Results Serum HSP70 levels in ACS group(4.72±2.01 μg/L)were significantly higher than those in SAP group(2.33±1.44 μg/L)and non-CHD group(2.41±0.96 μg/L;P><0.01).But the difference of serum HSP70 levels between SAP group and non-CHD group was not statistically significant(P>0.05).Among patients with CHD,serum HSP70 levels in AMI group(5.94±1.98 μg/L)were much higher than those in UAP group(3.49±1.10 μg/L;P><0.01),and serum HSP70 levels in UAP group were much higher than those in SAP group(2.33±1.44 μg/L;P><0.01).Serum HSP70 levels were associated positively with WBC(r=0.337,P><0.01),CK-MB(r=0.653,P><0.01)and hs-CRP(r=0.658,P><0.01),but negatively with HDLC(r=-0.211,P><0.05)among all the subjects.Conclusion Serum HSP70 levels may be valuable to predict the unstable plaque and evaluate the severity of ACS.