In order to protect the coastal and marine environment in South-East Asia，a number of cooperative governance mechanisms were established. According to the participants，these mechanisms can be divided into three categories：the ASEAN with ASEAN countries as participants，protection mechanisms established by ASEAN countries and some international organizations，and cooperative governance mechanisms established by ASEAN countries with other regions’ states. In the construction of cooperative governance mechanisms for protecting marine environment in the South-East Asia，the participatory capacities of these ASEAN countries are constrained by three challenges.（1）ASEAN’s capacities of marine environment management are weak；（2）In cooperation with international organizations and other countries，ASEAN countries didn’t take initiatives；（3）ASEAN countries adopted different legal systems，which increase the difficulty of nation-nation coordination and the integration between nations and non-nation actors，so it is not easy for them to achieve a comprehensive marine environment governance system.