["Family Relations, EarlyView. ", "\nABSTRACT\n\nObjective\nThis study examines trends in older adults' care arrangements in China in the context of family modernization, focusing on changes in the reported primary caregiver when older adults feel unwell.\n\n\nBackground\nFamily modernization and structural transformation in China may be placing growing pressure on the filial piety‐based family care model and reshaping older adults' care arrangements.\n\n\nMethods\nUsing data from the Chinese Longitudinal Healthy Longevity Survey (1998–2018), this study employed a hierarchical age‐period‐cohort model to analyze age, period, and cohort patterns in spousal care, adult children's care, and nonfamily care among 54,971 older adults, with mechanism and heterogeneity analyses.\n\n\nResults\nAge effects follow life‐course dynamics: with advancing age, reliance on spousal care decreases, whereas dependence on adult children increases. Nonfamily care follows an inverted U‐shaped trajectory, least common among the young‐old and oldest‐old. Period effects show that care from adult children has declined over time, while spousal care has increased and nonfamily care remains limited in scale despite becoming somewhat more visible in recent years. Changes in family‐based care arrangements are partly associated with market transition. Overall cohort effects are not evident, but gender‐specific patterns in adult children's care differ markedly across birth cohorts. Period effects also differ by residence, with only rural older adults experiencing a sustained decline in adult children's care.\n\n\nConclusion\nCare arrangements are being reorganized within a still family‐centered system, with spousal caregiving becoming increasingly important.\n\n\nImplications\nPolicies should strengthen support beyond the family, especially for spousal caregivers and rural older adults.\n\n"]