Introduction: Atherosclerosis is the most important cause of increasing coronary heart disease. When cholesterol LDL-C levels are low, an increase in Apo B is associated with 60% of the cardiovascular risk factors. This study find out the association between serum Apolipoprotein B levels with the degree of coronary artery lesions Methods: The study consists of 110 patients who were diagnosed with a meaningful damaged coronary artery through angiography at Hoan My Da Nang hospital, from March 2018 to September 2019. Research method: cross-sectional description. Results: The average value of serum Apo B in group 1 was 133.67 ± 17.56 mg/dl, and in group 2 it was 113.92 ± 16.78 mg/dl. The difference is statistically significant, p <
0.01. Cardiovascular risk factors in the study did not have a meaningful effect on serum Apo B levels. Dyslipidemia does not have a strong correlation with serum Apo B levels. Thereby, it is possible to recognize serum Apo B as an independent indicator along with other cardiovascular risk factors. Serum Apo B levels increase linearly according to the number of damaged coronary artery branches. There is a proportional correlation between serum Apo B levels and the degree of coronary artery lesions (r = 0.48, p <
0.01). Conclusion: Apo B is associated with the degree of coronary artery lesions