Based on the precipitation of Meiyu at 37 stations in the ChangjiangHuaihe riv er valley from 1954 to 2001 and the mean monthly reanalysis SST data (grid:2° ×2°) of NCEP/NCAR from 1953 to 2001, the relationship between Meiyu precipit ation and the sea surface temperature in the West Pacific Ocean are investigat ed in terms of empirical orthogonal function(EOF), composite analysis, singular value decomposition (SVD), and so on. Results show that the key SST region which influences lies in the warm pool of the West Pacific Ocean and the key pe riod is from December of the former year to February in the next year(simply cal led “former winter"). Meiyu precipitation is increasing (decreasing) in the cor responding period when SST of the warm pool in the West Pacific Ocean in the win ter is warmer (colder) than average. Results of SVD are consistent with those of composite analysis, which passed the prominent test of MonteCarlo at 0.0 5.