The invention belongs to the fields of laboratory medicine, clinical medicine, biotechnology and biochemistry, and relates to a serologic biomarker for coronary heart disease (CHD) detection, and application thereof. The biomarker is human SAMD3 (sterile alpha motif domain-containing protein 3). The biomarker is closely related to CHD incidence and development; SAMD3 is used as the biomarker for CHD incidence prediction and CHD development degree judgment, so that compared with the conventional pathological type diagnosis of CHD incidence and prognosis, the biomarker can more individually and accurately predict the early incidence situation and grade malignancy of CHD; moreover, the marker can be used for preparing a kit for screening CHD or assisting in pathological identification, clinical diagnosis and subtype discrimination of CHD.