【Purpose/significance】 This paper analyzes the mechanism of online health information chain communication from the per⁃

spective of group participation, and constructs an online health information chain communication model, which provides a basis for un⁃derstanding and exploring the impact of group participation behavior on online health information communication and its quality, and improving the governance effect of online health information quality.【Method/process】 Based on the communication process, commu⁃nication law and effect of online health information, this paper constructs a three-dimensional model of online health information chain communication, which is composed of information movement process, information communication effect and information quality.Taking the communication of "Helicobacter pylori" topic information in Weibo as an example, this paper explores the characteristics of topic information chain communication and the interaction among different elements.【

Result/conclusion】 It reveals the internal re⁃lationship between "information and users". Group participation makes the communication process of online health information show the characteristics of circulation and splitting, and makes the information quality show the law of bidirectional change. And the change of quality attribute and content characteristic in the process of information movement and communication also affects the group partici⁃pation behavior imperceptibly.【Innovation/limitation】 A three-dimensional model of online health information chain communication from the perspective of group participation is constructed, but the impact of group heterogeneity is not analyzed.