【Purpose/significance】The prevention of major chronic diseases is a major proposition of the times under the perspective of

the Health China Strategy, and the construction of a knowledge service system for the prevention of major chronic diseases can help ac⁃tively respond to and realize the requirement of "prevention and health-centeredness".【Method/process】The research on the charac⁃teristics of major chronic disease' prevention knowledge and knowledge service was sorted out. Through analyzing the existing knowl⁃edge service system construction research, we found that the major chronic disease prevention knowledge service system under the per⁃spective of Health China strategy has the characteristics of intelligent collaboration and active service, thus constructing the major chronic disease' prevention knowledge service system from four hierarchies of resources, technology, knowledge and application under the perspective of Health China strategy.【Result/conclusion】 Prevention knowledge resources of major chronic disease are widely dis⁃tributed on the Internet and public information channels, individuals and families, communities, grassroots units, and governments,etc. Big data and artificial intelligence technology can effectively cope with the complexity and ambiguity of major chronic disease'prevention knowledge and realize intelligent and collaborative proactive knowledge services, and focus on the application of intelligent screening of major chronic diseases, intelligent monitoring, personal health management and other scenarios.【Innovation/limitation】Introducing theories of intelligent collaboration and active services to build a knowledge service system for major chronic disease pre⁃vention in the perspective of the Health China strategy.