Abstract： Background High-density lipoprotein cholesterol(HDL-C)levels are a strong,independent inverse predictor of coronary heart disease (CHD).In this cross-sectional study we investigated the interrelationships between HDL-C and HDL relaled factors apolipoprotein A-I(apoA-I)and serum amyloid A(SAA)and the presence and extent of CHD in a population of Chinese patients with CHD. Methods Two hundred and twenty-four consecutive patients took part in this study.Demographic data were obtained from hospital records.Serum chemical concentrations were measured by standard laboratory methods.Reaults The concentrations of high-sensitive C-reactive protein(hsCRP)(median:1.85 mg/L)and SAP,(median:9.40 mg/L)were significantly higher in the CHD group(P<0.05),while concentrations of HDL-C(0.03±0.25)mmol/L)and apoA-I((604.59±1 05.79)mmol/L)were significantly lower than those in the non-CHD group(P<0.05).The concentrations of apoA-l decreased with the increase in vascular damage.but the difference did not reach statistical significance.However, the concentrations of hsCRP and SAA increased with the increase in vascular damage.The unadjusted odd ratios(ORs)(CI) for apoA-I and SAA of the presence of CHD were 0.093(0.990-0.997)(P=0.00)and 2.571(1.029-6.424)(P<0.05),respectively.The association between elevated SAA and the presence of CHD was lost after adjusting for lipid status parameter concentrations.The associations between apoA-I.SAA and the extent of CHD remained strong,regardless of confounding variables.Conclusions Increased concentrations of SAA represent the inflammatory marker of the extent of coronary stenosis in patients with CHD.In contrast to SAA, the level of apoA-I was also associated with the presence of CHD, indicating that apoA-I was not only a marker of CHD presence but also a quantitative indicator of CHD extent.In short.determining the change apolipoprotein content within HDL particle is a more accurate and effective method to evaluate the impact of HDL on CHD.