Background Less studies were done to compare the lipid ratios including ApoB100 / ApoA1, LDL-C / HDL- C,TC / HDL-Cin elderly. So the study was to investigate the relationship between Apolipoprotein B100 / ApoA1 ratio and coronary artery disease (CAD) in elderly. Methods 498 participants aged over 65 years with chest pain had been subsumed from Sep. 2009 to April 2011 of Guangdong General Hospital. Clinic informations of gender, age, history of hypertension, diabetes mellitus, smoking was collected. Simultaneously, serum lipids should be phlebotomized in 24 hours after be inpatient. ApoB100 / ApoA1 ratio, LDL-C / HDL-C ratio. TC / HDL-C ratio, non-HDL-C were calculated using the above data. Accroding to the mean of ApoB100 / ApoA1 ratio, ApoB100, non-HDL-C, all individuals were divided into two groups: high level group and low level group, while all individuals were divided into two groups whether the level of LDL-C was achieve 2.06 mmol / L. We classified the participants into CAD group and non-CAD group on the basis of CAG. The incidence of CAD was compared between the two groups of four different lipid indicators. The ability of estimating CAD was described by Reciever Operating Characteristic curve(ROC curve). Result There were significantly statistical differences in the incidence of CAD between the high level group and low level group of ApoB100 / ApoA1 ratio (75.0% vs. 55.9%, χ2 = 19.681, P < 0.001). By logistic regression analysis, odds ratio of ApoB100 / ApoA1 ratio was 2.142, 95% CI (1.437, 3.195)(P < 0.001). The AUC (area under curve) of ApoB100 / ApoA1 ratio were 0.66. There were significant for diagnosis of CAD (P < 0.001). Conclusion The ApoB100 / ApoA1 ratio was an independent risk factor of CAD in elderly population, and it is better than traditional lipid indicators, and can be used for the ability of estimating CAD. Background Less studies were done to compare the lipid ratios including ApoB100 / ApoAl, LDL-C / HDL-C, TC / HDL-Cin elderly. So the study was to investigate the relationship between Apolipoprotein B100 / ApoAl ratio and coronary artery disease (CAD Methods 498 participants aged over 65 years with chest pain had been subsumed from Sep. 2009 to April 2011 of Guangdong General Hospital. Clinic informations of gender, age, history of hypertension, diabetes mellitus, smoking was collected. Simultaneously, serum ApoB100 / ApoAl ratio, LDL-C / HDL-C ratio. TC / HDL-C ratio, non-HDL-C were calculated using the above data. Accroding to the mean of ApoBlOO / ApoA1 ratio, ApoB100, non-HDL-C, all individuals were divided into two groups: high level group and low level group, while all individuals were divided into two groups whether the level of LDL-C was achieved 2.06 mmol / L. We classified the participants into CAD grou p and non-CAD group on the basis of CAG. The incidence of CAD was compared between the two groups of four different lipid indicators. The ability of estimating CAD was described by Reciever Operating Characteristic curve (ROC curve). differences in the incidence of CAD between the high level group and low level group of ApoB100 / ApoA1 ratio (75.0% vs. 55.9%, χ2 = 19.681, P <0.001). By logistic regression analysis, odds ratio of ApoB100 / The AUC (area under curve) of ApoB100 / ApoA1 ratio were 0.66. There were significant for diagnosis of CAD (P <0.001). Conclusion The ApoB100 / ApoA1 ratio was an independent risk factor of CAD in elderly population, and it is better than traditional lipid indicators, and can be used for the ability of estimating CAD.