Based on the 1950—1998 SST and NCEP/NCAR reanalysis data,the temporal/spatial variations of SSTA in the Western Pacific Warm Pool region have been analyzed in this paper by means of the methods of EOF and composite analysis.Results show that there are two main spatial patterns of the WP SSTA:one is uniform in the whole region,the other is meridionally anti-symmetric.When the spatial pattern of SSTA is uniform in the whole region,in the warm years,an anticyclonic anomaly circulation exists over the warm pool and the westerly/easterly in the subtropical/tropical region are greatly strengthened at 850hPa,while an anticyclonic anomaly circulation over the India region at 200hPa,and the Walker circulation are strengthened,and vice versa.When the spatial pattern is meridionally anti-symmetric,in the north-warm/southcold years,an anticyclonic anomaly circulation exists over the warm pool at 850hPa,the easterly near 15°N and the westerly near the equator are greatly strengthened,while the center of the 200hPa anticyclonic circulation moves to the East Asia,and the Hadley circulation is affected evidently,so the summer rainfall may be above normal in the middle and lower reaches of the Yangtze River,and vice versa.