[Purpose/significance]Online health information seeking on behalf of others is a common approach of social support. Exploring the influencing factors of online surrogate health information seeking behavior will provide a theoretical contribution for understanding the behavior of surrogate seekers in the health domain. [Method/process]In this paper, a semi-structured interview was conducted with 18 users who had experience of online surrogate health information seeking. We used grounded theory to code interview data, and explored the formation mechanism and influencing factors of online surrogate health information seeking behavior. [Results/conclusion]Through the three-step coding process, we get 30 initial concepts, 13 categories and their corresponding 4 main categories, including patient needs, surrogate seekers' psychological motivation, surrogate seekers' cognitive motivation and environmental factors. Finally, we proposed a model of influencing factors of surrogate health information seeking behavior in the Internet environment.