To assess urban-rural differentials in age-related biological risk among middle-aged and older Chinese and links to individual and community characteristics. Data come from the national baseline survey of the China Health and Retirement Longitudinal Study. Biological risk is assessed using a set of measured biomarkers that reflect cardiovascular, metabolic, and inflammatory processes. Urban residents who are officially registered in urban areas have greater biological risk than rural residents. Having junior school or higher education provides an independent and persistent protective effect against biological risk and eliminates the effect of community-level measures. The reduced physical activity of urban dwellers with urban origins explains a substantial part of the difference in risk. Urban dwellers with urban household registration have elevated risk compared with their rural peers, indicating that lifetime exposure to urban areas is an important risk factor for increased biological risk in China. The urban-rural differential in risk is accounted for by adjusting for health behaviors, particularly physical activity. The reduced physical activity among urban dwellers with urban household registration appears to be highly related to their elevated risk. No significant associations between community-level characteristics and biological risk are found beyond individual characteristics.