The onset of the South China Sea Summer Monsoon (SCSSM) indicating the arrival of the rainy season of Eastern China is a key factor for the short-term climate prediction. The advances in the research about the characteristics, interannual variation of SCSSM onset, and the influence of external forces and internal processes on the SCSSM onset are reviewed in this paper, and the impacts of Intraseasonal Oscillation (ISO) on the SCSSM onset are also summarized. Some issues, such as the monsoon wave interaction, SCSSM change under global warming, the predictability of the SCSSM onset, etc., are introduced for further study in future.