Objective To conduct a meta-synthesis of the experience of dementia patients and their relatives in advance care planning（ACP） and provide evidence-based guidance for the development and implementation of ACP in dementia patients. Methods 8 databases（Web of science,PubMed,EBSCO,The Cochrane Library,Embase,CNKI,CBM,Wan Fang） were included to retrieve the literature on the experience of dementia patients and their relatives about ACP intervention from inception until August 2021. The quality of included studies was evaluated according to JBI Critical Appraisal Tool for qualitative studies in Australia. Meta-aggregation was used to conduct the synthesis. Results 41 findings were extracted from 11 qualified studies and they were integrated into 9 categories. 4 synthesis results were summarized,including attitude of dementia patients and their families to participate in ACP,the perceived benefits of dementia patients and their families to participate in ACP,the perceived barriers of dementia patients and their families to participate in ACP,and the perceived reactions of dementia patients and their families to participate in ACP. Conclusion The successful implementation of ACP requires continuous focus on the attitude of dementia patients and their families for participation. At the same time,facing the difficulties of dementia patients participating in ACP,we should alleviate the negative influence of family members’ participation and attach importance to patient preferences and enrich the content and form of ACP to promote the development and improvement of ACP.