Aim To evaluate the relationship between unstable plaques and the levels of high-sensitivity C-reactive protein(hs-CRP)and interleukin-6(IL-6)by intravascular ultrasound(IVUS).Methods 38 patients diagnosed with coronary heart disease by IVUS examination were chosen.Eight patients by IVUS examination were found with no coronary artery stenosis as control group,30 cases by IVUS examination were found with coronary artery stenosis as coronary heart disease group,including 18 cases with unstable angina pectoris(UAP)and 12 cases with stable angina(SAP).Serum hs-CRP and IL-6 levels of all patients were detected.Results 38 patients had varying degrees of intimal thickening.IVUS showed that 30 cases of coronary heart disease patients had different types of atherosclerotic plaque.Serum hs-CRP and IL-6 levels in UAP group were significantly higher than that in SAP group and control group.Serum hs-CRP and IL-6 levels were higher in unstable plaque group than those in stable plaque group.Conclusion Serum hs-CRP and IL-6 was significantly higher in the UAP patients.It prompted that the levels of hs-CRP and IL-6 could reflect the instability degree of atherosclerotic plaque.