As the main participants in the collaborative governance of multiple entities in the platform economy, platform enterprises not only possess the dual attributes of market neutrality and corporate profit seeking, but also have the dual identities of regulators and regulated entities, which greatly increases the difficulty of platform economy governance. This paper addresses the issue of dual-identity platform enterprises participating in multi-agent collaborative governance. It introduces real-world cases for empirical analysis and creatively proposes a novel two-dimensional spatial strategy set analysis framework. Building on the traditional evolutionary game theory, it constructs a 33 evolutionary game model and conducts a sensitivity analysis of stability. Research has found that when platform companies play the role of regulators, government departments act as regulatory “regulators” to supervise them. Consumer reports can suppress platform merchants’ illegal business behavior, while excessive joint liability of platform companies can actually undermine their enthusiasm; When platform enterprises play the role of regulated entities, government departments act as regulators to supervise the monopolistic behavior of platform enterprises. The cost and additional benefits of monopoly are the main basis for platform enterprises to choose monopoly strategies. Lawsuits by platform users in a disadvantaged position can only alleviate the monopolistic behavior of platform enterprises, but cannot fundamentally deter them.