With its flexible and convenient learning methods, rich learning resources and convenient information transmission channels, the online learning community has injected new impetus into the cause of education. However, the open and generative characteristics of the online learning community also preclude learning activities from implementing collective constraints, resulting in the emergence of knowledge hiding behavior. Based on this, researchers have attempted to explore the factors that affect knowledge hiding behavior and to identify the influencing mechanisms. Using structural equation modeling (SEM) and exploratory factor analysis (EFA), this study analyzed a questionnaire on the knowledge hiding behavior of 420 graduate students in online learning communities and found that professional commitment, transformational leadership and a proactive personality have a negative impact on knowledge hiding behavior through self-efficacy and organizational psychological ownership. Based on the model interpretation, this paper suggests that the following aspects should be explored for their potential to diminish knowledge hiding behavior: Assess the proactive personality level of graduate students; the training unit can stimulate students’ self-efficacy in terms of the expected results, rewards, relationships and perceived costs of the individual; the supervisor should establish and improve the knowledge sharing mechanism within the organization; the tutor should strengthen the cultural construction of the scientific research team.