The prevalence and influencing factors of metabolic syndrome (MetS) in Chinese residents aged 20 or older were investigated. The data were collected from China Nutrition and Health Surveillance (2015-2017), which used a stratified, multistage, random sampling method. A total of 130,018 residents aged 20 years or older from 31 provinces were included in this study. The National Cholesterol Education Programme Adult Treatment Panel III (NCEP ATP III) criteria were used to define MetS. The standardised prevalence of high waist circumference, high blood pressure and low high-density lipoprotein cholesterol were 40.8%, 49.4% and 41.1%, respectively. The following factors were associated with a higher prevalence of MetS: female [odds ratio (OR) = 1.773, 95% CI = 1.709-1.840]; older age (OR = 1.037, 95% CI = 1.036-1.039); living in north China (OR = 1.087, 95% CI = 1.058-1.117); high body mass index (OR = 1.402, 95% CI = 1.395-1.408); higher income [OR (95% CI): 1.044 (1.007-1.083), 1.083 (1.044-1.124) and 1.123 (1.078-1.170) for moderate, high, and very high income, respectively]; family history of hypertension (OR = 1.237, 95% CI = 1.203-1.273); family history of diabetes (OR = 1.491, 95% CI = 1.426-1.558) and current smoking status (OR = 1.143, 95% CI = 1.098-1.191). Living in the countryside (OR = 0.960, 95% CI = 0.932-0.988), moderate alcohol consumption (OR = 0.917, 95% CI = 0.889-0.946) and being physically active (OR = 0.887, 95% CI = 0.862-0.913) were associated with a lower prevalence of MetS. The prevalence of MetS among residents aged 20 years or older in China is increasing, especially among women, people aged 45 years or older and urban residents. Preventive efforts, such as quitting smoking and engaging in physical activity, are recommended to reduce the risk of MetS.