<p>Family caregiving for older adults (FCOA) is a critical issue for achieving sustainable social development. Using data from the 2024 China Time Use Survey and a supply-demand analytical framework, this paper examines the spatial patterns and determinants of FCOA in China. The findings reveal four main results. First, participation rates and duration of FCOA exhibit significant regional heterogeneity: northeastern and northwestern regions show a dual-high pattern (high participation and long duration), while the southeastern coast shows a dual-low pattern. Second, in most provinces, urban care duration exceeds rural care duration, and women bear the primary caregiving burden. Third, out-migration mainly compresses care duration; the share of stem families suppresses participation through intergenerational competition effects, while market-oriented institutions exert a comprehensive substitution effect; care duration for disabled older adults displays strong demand rigidity. Fourth, urban caregiving is shaped by multiple factors including family structure and market-based services, whereas rural caregiving is primarily affected by the shock of population out-migration. The paper offers empirical insights for developing countries to optimize the allocation of family care resources and advance sustainable social development.</p>