Objective To study the effectiveness of waist circumference cut-off values in predicting the prevalence of metabolic syndrome(MetS) and risk factors in adults in China. Methods A cross-sectional survey was condcuted in 14 provinces(autonomous region, municipality) in China. A total of 47 325 adults aged ≥20 years were selected by multistage stratified sampling, and questionnaire survey and physical and clinical examination were conducted among them. MetS was defined according to the International Diabetes Federation(IDF) criteria and modified IDF criteria.Results The age-standardized prevalence of MetS was 24.2%(22.1% in men and 25.8% in women) and 19.5%(22.1% in men and 18.0% in women) according to the IDF criteria and modified IDF criteria respectively. The age-standardized prevalence of pre-MetS was 8.1%(8.6% in men and 7.8% in women) according to the modified IDF criteria. The prevalence of MetS was higher in urban residents than rural residents and in northern China residents than in southern China residents. The prevalence of central obesity was about 30% in both men and women according to the ethnicity-specific cut-off values of waist circumference for central obesity(90 cm for men and 85 cm for women). Multivariate regression analysis revealed no significant difference in risk factors between the two MetS definitions. Conclusion Using both the modified IDF criteria and ethnicity-specific cut-off values of waist circumference can provide more useful information about the prevalence of MetS in China. Objective To study the effectiveness of waist circumference cut-off values ​​in predicting the prevalence of metabolic syndrome (MetS) and risk factors in adults in China. Methods A cross-sectional survey was condcuted in 14 provinces (autonomous region, municipality) in China. A total of 47 325 adults aged> 20 years were selected by multistage stratified sampling, and questionnaire survey and physical and clinical examination were conducted among them. MetS was defined according to the International Diabetes Federation (IDF) criteria and modified IDF criteria. Results The The The age-standardized prevalence of MetS was 24.2% (22.1% in men and 25.8% in women) and 19.5% (22.1% in men and 18.0% in women) according to IDF criteria and modified IDF criteria respectively. The age-standardized prevalence of pre-Met was 8.1% (8.6% in men and 7.8% in women) according to the modified IDF criteria. The prevalence of MetS was higher in urban residents than rural residents and in northern China residents th an in southern China residents. The prevalence of central obesity was about 30% in both men and women according to the ethnicity-specific cut-off values ​​of waist circumference for central obesity (90 cm for men and 85 cm for women). Multivariate regression Conclusion Using both the modified IDF criteria and ethnicity-specific cut-off values ​​of waist circumference can provide more useful information about the prevalence of MetS in China.