Purpose: To examine the support from different sources of Chinese families of patients with moderate-to-severe dementia that most heavily influences the family adaptation and the influence pathway. Method: Two hundred and three families participated in this study. Chinese versions of instruments were used. Structural equation modeling was applied to confirm the effect pathway. Results: More family support, kin support, community support, and social support (narrow sense) were related to greater levels of family adaptation. Family support was the most heavy influence factor (total effect = 0.374), followed by kin support (0.334), social support (0.137), and community support (0.121). Family support and kin support were direct influence factors, while the other 2 were not. Conclusion: All support will promote family adaptation, especially family support and kin support. Interventions improving support from different sources, especially family support and kin support, will promote adaptation in Chinese families of patients with moderate-to-severe dementia.