Abstract： Objective To evaluate the clustered characteristics of the components of metabolic syndrome. Methods 483 subjects (242 men, 241 women, aged 53±12 years ) in Beijing area underwent a 75g oral glucose tolerance test (OGTT) for screening of diabetes.203 subjects were diagnosed as diabetes through OGTT.Factor analysis was performed using the variables of insulin/blood glucose, total cholesterol (CHO), LDL-C, HDL-C, triglycerides (TG), systolic blood pressure, diastolic blood pressure, BMI, waist-to-hip ratio and waist circumference. Results Five factors, including obesity, insulin resistance/hyperglycemia, CHO/LDL-C, dyslipidemia (elevated TG and decreased HDL) and hypertension, could explain 72.2% of total variance.The most important component was obesity, which could explain 29.8% of total variance.The obesity factor was associated with dyslipidemia factor through C-reactive protein (CRP).Dyslipidemia factor also associated with insulin resistance/hyperglycemia factor.Hypertension factor and CHO/LDL-C factor were isolated from other factors. Conclusions Obesity factor is the most important component of metabolic syndrome.The pathophysiologic mechanism of metabolic syndrome is complex.Insulin resistance alone could not explain all features of the metabolic syndrome.Its pathophysiology maybe include the factors of obesity, insulin resistance and inflammatory reaction.