Phytoplankton bloom is considered to be one of the most important scientific issues of marine biology. It is also the key factor of marine carbon cycle under the background of global changing,for which can rapidly and sensitively response to climate changes. The background and significance of phytoplankton blooms in the South China Sea were studied and summarized in this paper,based on the research at home and abroad in recent years. Besides,the main research methods and contents of phytoplankton bloom in the South China Sea were focused and reviewed in this paper. Finally,the main problems and challenges in current study of phytoplankton bloom in the South China Sea were summarized,the future development trends and research directions of this field were prospected.