Abstract: Based on an analysis of the evolution of Shenzhen’s implementation mechanism for planning and building green public spaces, this paper examines the problems that have emerged in the new period, including weak transmission of action-oriented planning, insufficient coordination between sectoral and territorial responsibilities, fragmented construction activities, and inadequate policy support. Drawing on advanced international experience in implementing urban-level green public space systems, the paper argues that implementation mechanisms should pursue the integrated value orientation of positive externalities, systemic integration, collaborative action, and process-based governance. Taking Shenzhen’s “Mountain-SeaCity Linkage Plan” as an example, the paper shows how the city has built a society-wide consensus around the goal of creating a “green and beautiful home,” formulated an implementation scheme characterized by “system integration plus sustained relay,” established a collaborative framework combining “control, guidance, and service,” provided policy support throughout the “planning-construction-managementoperation” cycle, and created a governance platform for “co-construction, sharing, and co-governance.” In less than five years, the Plan has achieved substantial implementation results, demonstrating the effectiveness of a full-process implementation mechanism and offering useful references for transforming the supply mode of planning and design in the new era and for innovating implementation mechanisms for green public space planning and construction.