1 ASEAN in the Changing Asia Pacific Security Order Si Min Li siminzaihk@gmail.com Institute of China and Asia Pacific Studies National Sun Yat-sen University Abstract: This paper hopes to finds out ASEAN’s coping ways with several great powers in the changing Asia Pacific security order through reviewing its evolution, analyzing its strength and weakness and the interactions between five great powers namely America, China, Japan, India and Australia. It finds that smaller power has its own advantages. As a whole, ASEAN should enhance its internal cohesion and target one country on one issue. Also, for ASEAN, the way to see its institutional design and arrangement decides its version. If the long-standing constraints cannot be fixed, the disputes within ASEAN and crisis beyond ASEAN may break up the organization.