Inter-decadal variability characters of ocean-atmosphere interconnection in the tropical areas are investigated by the use of the NCEP/NCAR reanalysis data,the SST data set of GISST2.3b and the south oscillation index (I_SO) of CRU(Climate Research Unit).Results indicate that there exist remarkable inter-decadal variances of the ocean-atmosphere system in the tropical Pacific areas. In recent fifty years,the relationship between I_WP(the west Pacific seasurface temperature index in 125～155°E,10°S～10°N) and I_SO shows more obvious inter-decadal changes. The analysis of the atmospheric general circulation shows that when the correlation between I_WP and I_SO is weak and the West Pacific SST warmer (colder), there exists an anticyclonic (cyclonic) circulation in the lower troposphere over the northern equatorial western Pacific. In contrast to the typical low SST-anticyclone pattern in the ENSO phase,the dynamical effect of such a system is not in favor of maintaining a close correlation between I_WP and I_SO.