Non-communicable chronic diseases (NCDs) have become the top threat in China. This study aimed to estimate the prevalence of major NCDs among the elderly population in rural areas in southern China and explore its associated social determinants. Methods: A multistage cluster random sampling methodology was adopted to select a total of 9245 rural elderly people from 3860 rural households in Guangdong Province. Interviews and physical examinations were performed to collect patient information. Descriptive and logistic regression analyses were conducted to explore factors associated with the presence of major NCDs. Results: Over one-third (38.5%) of the study population suffered from five major NCDs. The grade of activities of daily living (ADL), mental status, and social relationship of elderly people without NCDs were better than those with NCDs. The Association Between Physical Activity, Mental Status, and Social and Family Support with Five Major Non-Communicable Chronic Diseases Among Elderly People: A Cross-Sectional Study of a Rural Population in Southern China