Objectives: Acculturation to the mainstream culture and the settlement contexts could shape cognitive function of older immigrants. Guided by ecological theory, this study examines the interaction effect between individual acculturation and ecology of family on cognitive function among older Chinese Americans. Methods: Data were derived from the Population Study of Chinese Elderly in Chicago (n = 3,019). Family types included tight-knit (high solidarity and low conflicts), unobligated-ambivalent (high solidarity and conflicts), commanding-conflicted (low solidarity and high conflicts), and detached (low solidarity and low conflicts). Acculturation was measured via language ability, media use, and ethnic social relations. Cognitive function was evaluated by global cognition, episodic memory, working memory, processing speed, and mini-mental state examination. Multiple regression analyses and interaction terms were used. Results: Older adults in the commanding-conflicted type had the lowest cognitive function. After controlling confounding variables, higher levels of acculturation (b = 0.009, SE = 0.003, p <.01) were associated with higher levels of global cognition. Acculturation buffered the negative impact of having a commanding-conflicted relationship with children on global cognition (b = 0.070, SE = 0.016, p <.001). Language ability, media use, and ethnic social relations played a unique role in the relationships between family types and cognitive domains. Conclusion: Acculturation to the dominant culture is identified as a cultural asset for cognitive function in older Chinese Americans. Social services could protect cognitive function of older immigrants in the commanding-conflicted type through enhancing cultural participation. Future research could test how affective and cognitive aspects of acculturation affect health.