Many developed and developing countries, including China, are facing the challenges of the aging population. One such challenge is the difficulty for some older adults to access nutritious hot meals to maintain their health and well-being. Community-based senior dining halls (CSDHs) providing low-cost meals for older adults are a widespread model across China and neighboring countries, which aim to cater to the dining needs of older adults within local communities. However, most CSDHs face financial difficulties due to low dining volume. Hence, understanding how built environment characteristics are associated with the dining volume can potentially increase the dining volume and financial sustainability of CSDHs in the long run. This study analyzed the association between the dining volume and both the external and internal built environment of 50 CSDHs in Guangzhou, China. By using multiple linear regression models with three different buffer sizes (400 m, 600 m, and 800 m), we found that 1) among the external built environment characteristics, floor area ratio (FAR) and distance to the nearest subway station are negatively linked to the dining volume; 2) among the internal built environment characteristics, floor level is negatively associated with dining volume, whereas availability of dine-in seating and water dispenser, and number of seats are positively associated with it. Hence, a well-designed external and internal built environment of CSDHs may increase dining volume, enhance social interaction among older adults, and support community-based senior care.