At present, the level of health literacy, social support, and care ability of dementia caregivers is not very high. Therefore, the purpose of this study was to construct a structural equation model to explore the relationship between health literacy, social support, and the care ability of dementia caregivers. It is hoped that the study will provide a theoretical basis for future intervention. We recruited 225 dementia patients and their caregivers from August 2018 to June 2019 at the Department of Geriatrics and Neurology. We issued a health literacy questionnaire, social support scale, and a care ability questionnaire. Statistical analyses were performed using SPSS 19.0 and SPSS Amos 23.0. The mean scores for health literacy, social support, and care ability were 13.93 +/- 4.18, 34.64 +/- 6.42, and 44.44 +/- 9.31, respectively. Health literacy was directly related to social support (path coefficient = 0.454). Social support was directly related to care ability (path coefficient = 0.293). Furthermore, health literacy was directly related to care ability (path coefficient = 0.561), while health literacy had indirect associations with care ability via social support (path coefficient = 0.133). This study showed that improving the health literacy of caregivers effectively improved their care ability, and that social support was important for the link between health literacy and care ability. Medical staff and family members can provide appropriate health education and social support according to the characteristics of caregivers to improve the care ability of caregivers, improve the quality of life of patients, and delay the disease process.