Under the policy background of digital transformation, the issue of multi-subject collaboration in grassroots smart governance has become the key to improving governance efficiency. This article applies the Actor Network Theory (ANT) and takes the “Quancheng Office” platform in J city as the research object to systematically analyze the construction path and practical effectiveness of its multi-subject collaboration mechanism. Research has found that grassroots smart governance requires the integration of heterogeneous actors through translation, forming a governance network that synergizes technology and institutions. Further research reveals the current practical difficulties and proposes optimization paths, providing a reference for the theory and practice of grassroots smart governance.