Objective To explore the relationship between homocysteine(Hcy)level and the severity degree of coronary artery disease in patients with coronary heart disease.Methods 192 patients from January 2013 to January 2014 in our hospital were selected as the research group,160 cases of them diagnosed by coronary angiography were selected as the coronary heart disease group,and 32 patients with normal coronary angiography were selected as the control group.The level of Hcy in different groups was compared.Results The level of Hcy in the coronary heart disease group was higher than that in the control group,with significant difference (P<0.01).The level of Hcy increased with the increased of Gensini score(P<0.05),and the level of Hcy increased with the increased number of coronary artery lesion.Conclusion The level of serum homocysteine can be used as an indicator to predict the severity degree of coronary artery lesion.