Abstract: 【Purpose/significance】From the perspective of peer influence, this paper explores the occurrence process and behavior
mechanism of knowledge co-creation on the basis of distinguishing the similarity between natural and social attributes of peers, provid? ing reference value for the deepening of theoretical research and the expansion of application practice on knowledge co-creation.【Method/process】Based on the generation process of peer influence, a knowledge co-creation behavior model was constructed 280 popular discussion posts on lung cancer in "YuAiGongWu" platform were taken as the research object, and 19,835 comments from 7796 users were obtained. After manual coding and standardized processing, data correlation analysis and regression analysis are real? ized.【Result/conclusion】This study classified peer interactions into two types of linear and spiral interactions and verified the signifi? cant positive relationship between perceived similarity and peer interactions. Both variables were able to significantly affect knowledge co-creation performance and were moderated by knowledge distance, showing positive moderation in linear interactions and negative moderation in spiral interactions.【Innovation/limitation】Distinguish the personal attributes of patients from nature and society, provide a new perspective for the study of user knowledge co-creation behavior in online health communities relying on the generation process of peer influence. However, this study only considers the user dimension when forming the behavioral mechanism of knowledge co-creation, and subsequent research can be supplemented from more aspects such as community platform and community environment.