Abstract

The 15th Five-Year Plan explicitly calls for supporting the establishment of international scientific and technological organizations (ISTOs) within China. Using the “international environment–policy instruments–organizational roles” framework, directed qualitative coding, periodization tests, and crossdimensional co-occurrence analysis are applied to 108 ISTO policies covering the 9th–14th Five-Year Plan periods (1996–2025). The findings identify three phases: the Institution Foundation Phase, the Network Expansion Phase, and the Ecosystem Construction Phase. Problem framing broadened from openness and cooperation to competition, multilateral dynamics, rules and security, and global governance. Instruments shifted from scattered incentives and regulation to supply-side projects, platforms, talent, and framework conditions; demand-side instruments remained limited in the latter two phases. Roles expanded from activity vehicles and regulated entities to cooperation connectors, network organizers, knowledge-service providers, and governance participants. Co-occurrence patterns shifted from environment–instrument to instrument–role linkages. The study recommends stronger international agenda planning, a balanced supply-side–demand-side–framework-condition policy mix, and institutionalized ISTO participation in S&T governance.