Abstract: AIM To investigate the role of SCD40L in the occurrence, development and correlativity of coronary heart disease(CHD)in patients with severe periodontitis. METHODS 63 patients were divided into healthy controls (n=14), severe periodontitis group (n=16), coronary heart disease group (n=19) and coronary heart disease in patients with severe periodontitis(n=14). Venous blood was taken to measure the concentration of SCD40L in serum. between coronary heart disease group and coronary heart disease in patients with severe periodontitis group of periodontal parameters (Probing depth, clinical attachment loss, bleeding on probing, plaque index and the remaining teeth) was determined. Correlation analysis between SCD40L and CAL, PD, PLI and BOP was performed to observe the correlation between SCD40L and periodontal parameters. RESULTS Compared with the healthy control group, coronary heart disease group and severe periodontitis group SCD40L was singificantly higher than the healthy control group (P<0.01). Compared with the severe periodontitis group and coronary heart disease, increased SCD40L level in coronary heart disease patients with severe periodontitis group and the difference was statistically significant (P<0.05). Compared with the group of coronary heart disease, remaining teeth number in coronary heart disease and severe periodontitis group was statistically significant (P<0.05), compared with the group of coronary heart disease Probing depth level in coronary heart disease and severe periodontitis group was deeper (P<0.05), CAL and BOP have was increased statistical significance (P<0.01). SCD40L and BOP had existed a positive correlation (P<0.05). CONCLUSION SCD40L can be used as a predictive factor for predicting the severity of coronary artery disease in patients with severe periodontitis.