As a new Internet product, webcast has been greatly sought after by netizens, and also attracted wide attention from academia and business experts. Combined with the use and satisfaction theory, and the system methodology of Wuli-Shili-Renli(WSR), this paper constructs a framework model of influencing factors for public participation in webcast. The structural equation model is used to construct the conceptual model of influencing factors, and empirically analyze the influence direction, degree and relationship of each factor. The results show that Wuli-Shili-Renli factors can significantly affect the public participation in webcast. This study provides method reference for promoting the healthy development of webcast platform.