Abstract: 【Purpose/significance】This study fully considers the characteristics of medical and health big data, identifies the influenc⁃ ing factors of medical and health big data quality as the research object, clarifies the hierarchical and structural relationships between factors, and promotes the development of the national medical and health big data strategy.【Method/process】Based on the theory of Total Quality Management (TQM), the factors affecting medical and health big data quality were identified by literature analysis, and the hierarchical relationship and internal relationship were analyzed by Fuzzy-DEMATEL and ISM.【Result/conclusion】The study found that medical and health big data quality is affected by 17 factors in 5 dimensions, among which there are 3 most direct influenc⁃ ing factors, including the professional quality of relevant personnel, stakeholder collaboration and information system, 9 pivot factors such as the supply and demand environment and the security environment connecting the bottom and top relationships, and 5 root fac⁃ tors such as political environment and cultural environment【. Innovation/limitation】Based on the TQM theory, this study systematically analyzes the factors affecting medical and health big data quality from the five levels of environment, organization, standards, informa⁃ tion technology and data attributes, which is innovative to some extent. The limitation is that the weight of the identified factors is not quantified in this study, and the role of each influencing factor can be specifically measured by the relevant weight calculation method in the future.