【Abstract】Objective To study the changes of serum free fatty acid (FFA) level and blood lipid level in patients with coronary heart disease and their correlation with the degree of myocardial injury. Methods Two hundred and fifteen patients with coronary heart disease enrolled in our hospital from January 2018 to January 2019 were included in the study. Among them, 97 patients with myocardial injury were included in group A, and 118 patients with nonmyocardial injury were included in group B. Another 80 healthy volunteers underwent physical examination during this period were included as the control group. Serum FFA and lipid levels were detected to analyze their correlation with the degree of myocardial injury. Results No significant difference was detected in total cholesterol, triglyceride, high and lowdensity lipoprotein levels among the three groups (P＞005), but FFA level of study group A was higher than that of study group B and control group, while FFA level of study group B was lower than that of study group A and control group (P＜005). The incidence of myocardial injury in normal lipid group was lower than that in abnormal group (P＜005). The FFA level of normal blood lipids in the study group was meaningless compared with that of abnormal blood lipids (P＞005). Conclusion The serum FFA level but not the serum lipid level is closely correlated with the degree of myocardial injury in patients with coronary heart disease. There was no significant correlation between FFA and lipid indicators. Therefore, serum FFA can be used as a good marker for detecting the degree of myocardial injury in patients with coronary heart disease, laying a foundation for clinical application.