【Purpose/significance】 In the face of public health emergencies, people tend to be afraid of missing important health risk

information and feel anxious. This paper reveals the formation mechanism of health risk information fear of missing out (FoMO) in pub⁃lic health emergencies and its impact on seeking behavior in order to improve the theoretical system of health information seeking be⁃havior research and further to provide important suggestions for optimizing health information seeking services and users' seeking be⁃havior.【Method/process】Based on SSO model, the research model is built by taking three-dimensional factors of person, information and environment as the stressor, considering FoMO as the strain, and regarding seeking behavior of health risk information as the be⁃havior outcome. Then research data collected through questionnaire is analyzed by SEM and ANN respectively.【Result/conclusion】The results show that FoMO is significantly influenced by event attention, neurotic personality, diversity of information selection, so⁃cial comparison tendency, and positively promotes active and passive seeking behavior of health risk information.【Innovation/limita⁃tion】 This paper explores the linear and nonlinear associated mechanism of antecedents on health risk information seeking behavior in order to make conclusions more scientific, and there is still to be improved in these aspects of the diversity of samples and the compre⁃hensiveness of influencing factors.