In terms of EOF analysis, the temporal and spatial features of sea surface tempe rature (SST) over Indian Ocean in four seasons are studied by using monthly mean SST data reanalyzed by the NCEP from 1950 to 1997. In addition, Composite anal ysis, Correlation analysis and Singular Value Decomposition (SVD) method have be en ap plied to analyze the relation between summer rainfall fields over Tibet Plateau and spring/summer SST anomaly over Indian Ocean. Finally, a key region of SST is found to offer forecasting Tibet Plateau summer rainfall.