Plasma homocysteine (Hcy) and C-reactive protein (CRP) levels are closely related to atherosclerosis. In this study, patients with coronary atherosclerotic heart disease were selected to examine changes of plasma Hcy and CRP expression levels and to analyze their relationship. Coronary atherosclerotic heart disease patients in our hospital were selected as the experimental group and healthy subjects in the same period were treated as the control group. The levels of serum Hcy and hs-CRP were tested and compared in coronary heart disease patients with different clinical types, vascular lesions, and coronary stenosis. The relationship among serum Hcy, hs-CRP, and coronary artery stenosis score was analyzed. The levels of serum Hcy and hs-CRP in SAP, UAP, and AMI patients were higher than those in the control group. The levels of serum Hcy and hs-CRP gradually increased among SAP, UAP, and AMI patients (P < 0.05). The levels of serum Hcy and hs-CRP gradually upregulated in single vessel disease group, double vessels disease group, and multi-vessel disease group (P < 0.05). The levels of serum Hcy and hs-CRP gradually elevated in patients with mild, moderate, severe stenosis, and entirely occluded (P < 0.05). Serum Hcy, hs-CRP, and coronary artery stenosis score exhibited positive correlation with each other (P < 0.05). Hcy and hs-CRP increased in coronary heart disease patients with more numbers of the pathological coronary vessels and severe coronary artery stenosis. Serum Hcy, hs-CRP, and coronary artery stenosis score exhibited positive correlation with each other.