As a national economic engine and gateway to openness，implementing a more open and integrated negative list stress test in the Guangdong-Hong Kong-Macao Greater Bay Area is not only needed for breaking policy and institutional barriers through expanded system-based openness but also needed for supporting China’s participation in higher-standard international free trade agreements and exploring further opening-up in advance. The basic conditions for implementing a more open and integrated negative list stress test in the Guangdong-Hong Kong-Macao Greater Bay Area are relatively sufficient，and it is completely safe and feasible as long as organizational，plan，and security preparations are in place. It is suggested to benchmark RCEP，CPTPP，and other high-standard international free trade agreements，and prioritize breakthroughs in market access，unified rule alignment，and investment trade liberalization and facilitation.