Objective To investigate the characteristics of homocysteine in patients with coronary heart disease (CHD) and the intervention effect of folic acid.Methods90 patients with coronary heart disease form internal medicine-cardiovascular department in the third affiliated Liwan hospital of Guangzhou Medical University from December 2015 to December 2016 as the study group.They were randomly divided into group A and group B, 45 patients in each group.The group A received routine treatment and Group B on the basis of conventional treatment plus folic acid.Another 90 healthy people who came to our hospital during the same period were selected as control group.The plasma homocysteine level of study group and control group were compared and plasma homocysteine level and angina status(frequency and duration of disease) of A and B group were compared before and after treatment.ResultsThe plasma homocysteine level of study group was significantly higher than that of the control group (P<0.05).After treatment, plasma homocysteine level,frequency and duration of disease of two groups were better than that of before treatment and B group was lower than that of A group(P<0.05).ConclusionThe results of plasma homocysteine levels can be used as an important basis for the clinical diagnosis of coronary heart disease and to determine its efficacy.