This study explores the influence of enterprise internal marketing on organizational citizenship behavior and the moderating effect of online community participation. The study used the questionnaire survey method and distributed 200 questionnaires to the T Company, and was received 178 usable responses. Results of hierarchical regression analyses show that (1) internal marketing was positively related to organizational citizenship behavior; (2) communication and incentive, training and managerial support of internal marketing were positively related to organizational citizenship behavior, and the relationship with training was strongest; (3) online community participation moderated the relationship between internal marketing and organizational citizenship behavior; (4) online community participation moderated the relationship between training and managerial support of internal marketing and organizational citizenship behavior, and between internal marketing and protecting enterprise resource of organizational citizenship behavior.