As ecological civilization has been elevated to a national strategic goal, urban grassroots river governance faces the dual challenges of systemic transformation and capacity enhancement. This paper summarizes an innovative river governance model: “umbrella-style co-governance”, a collaborative mechanism combining government leadership with social participation. Through structural, procedural, and technological coordination, participants form a governance system characterized by collaboration and coordination, flattened information flow, and closed-loop problem resolution, thereby improving response speed, resource allocation efficiency, and public participation. The findings indicate that the “umbrella-style co-governance”can help construct a collaborative governance structure characterized by complementary functions and operational autonomy, significantly enhancing end-level river and lake governance efficiency and implementation capacity. Through institutionalized social embeddedness, “umbrella-style co-governance” model promotes sustained multi-actor participation and strengthens ecological, social, and institutional outcomes.