Abstract: With the deepening fuse of medical health information and the internet, online health information seeking behavior has been more frequent, and it is increasingly important to understand it from a macroscopic perspective. Based on the information ecology perspective, it collected 40 college students' network health information search data by semi-structured interview to explore the five factors involved in the network healthy information search behavior under the information ecology perspective, i.e. information users, network health information, other groups, information platforms and social environment and their interaction. Firstly, the factors of finding individual characteristics, willingness to use, information value, platform service, interactivity, social ethos and other 17 topics (including 36 sub-themes) affect the behavior of network healthy information search. There are differences and similarities in the roles and manifestations of these influencing factors in the five factors of information ecological environment. Secondly, there are 10 pairs of interactions among the five factors involved in the online healthy information search behavior, which are different in the "distance ", the intensity of the interaction and the degree of influence on the search behavior. This paper introduces the information ecology theory into the information search behavior, makes up the information ecology theory about the information search behavior research, provides the certain theory basis for exploring the users' search behavior influence factor and the interaction relation, and is advantageous to guide the users to search the healthy information.

Key words: Information ecology, Health information search, User behavior, Interaction relationship, College students