Abstract: In the we-media era, traditional speech governance models are unable to cope with the increasingly complex, diverse, and chaotic cyberspace. It is necessary to incorporate public participation into the process of governing speech on social media platforms. Public participation in platform speech governance not only has social and economic legitimacy but also aligns with the values of policies and laws. Currently, there is no clear legal obligation for platforms to ensure public participation in speech governance, which leads to substantial obstacles to meaningful public engagement. On an operational level, there are also barriers to public participation in platform speech governance: firstly, the public's governance capabilities do not fully align with the expertise required for speech governance, thereby affecting governance efficiency to some extent; secondly, public participation may increase compliance risks for platforms, reducing their willingness to promote democratic governance. To address these issues, it is important to ensure public participation in platform speech governance through three perspectives: clarifying the platforms' obligation to safeguard public participation, precisely defining the scope of public involvement, and establishing a "safe haven" system for public participation in speech governance.