Abstract: Using NCEP/NCAP reanalysis data, SST data set of GISST2. 3b, South Oscillation Index (SOI) of CRU as well as the surface air temperature/rainfall records from 160 stations in China, the relation among the western Pacific SST index, the southern oscillation index and the surface air temperature/rainfall in China in winter is investigated. Results indicate that, the relationship between WPI and SOI shows obvious inter-decadal changes in the winter during recent fifty years. When the correlation between WPI and SOI is weak and the western pacific SST warmer (colder), there exists anticyclone (cyclone) circulation at the lower troposphere over northern equatorial western pacific, which is not in favor maintaining a close correlation between the West pacific SST and ENSO. Accordingly, through the whole troposphere, such system Presents quasi-barotropic structure in the winter. Furthermore, when the correlation between WPI and SOI is strong (weak or reversed), the correlation between WPI and the surface air temperature/rainfall in China is weak (strong) in the winter.