The South China Sea is known as an area where the Chinese government stands against its Southeast Asian neighbors in unresolved sovereignty conflicts over the disputed islands and the exploration for natural resources. Therefore, the South China Sea presents challenges for multilateral environmental cooperation. China was not an active participant in the multilateral environmental cooperation in the South China Sea before the 1990s. However, the approval of the United Nations Environmental Programme (UNEP)/Global Environmental Facility (GEF) South China Sea Project in 1999 marked a dramatic attitude change by the Chinese government towards the South China Sea environmental protection. It is the first multilateral inter-governmental initiative signed by China on any issues related to the South China Sea. Before signing its approval of the UNEP/GEF South China Sea Project, the Chinese government strongly opposed any multilateral cooperation concerning the South China Sea, since most of the islands in the South China Sea are territorially disputed islands between China and other coastal countries. This thesis tries to find the reasons why China changed its attitudes on the multilateral environmental cooperation in the South China Sea. Based on an analysis what happened for China from 1995 when the UNEP/GEF South China Sea project was initiated, to 1999, when China approved this project, this thesis found that the motivations for China to participate in the multilateral environmental cooperation in the South China Sea are collective of national interests, rather than a pure environmental interest. / Master of Arts