Objective To investigate the correlation between moderately and severely chronic periodontitis and coronary heart disease, as well as the role of fibrinogen in the mechanisms responsible for the correlation between periodontitis and coronary heart disease. Methods 95 subjects who were systemic health or patients of coronary heart disease with or without periodontitis were enrolled. All the subjects were placed into 4 groups based on their periodontal status and cardiovascular health. The 4 groups were healthy control group（HC）, moderately and severely chronic periodontitis group（MSP）, coronary heart disease group（CHD）, and MSP coexisted with CHD group（MSP+CHD）. Clinical periodontal index were examined, at the same time, plasma fibrinogen levels and serological changes used in diagnosing of cardiovascular disease routinely were determined. ANOVA and ANCOVA were used in the statistical analysis. Results Fibrinogen levels of HC, MSP, CHD, and MSP+CHD group were（2.36±0.37）, （3.63±0.73）, （4.08± 0.84）, and （4.14±0.96）g/L, respectively. Fibrinogen levels of MSP and MSP+CHD group were significantly higher than that of healthy controls（P
