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The interdecadal variability of the basic mode of global zonal-mean atmospheric circulation was analyzed with the monthly reanalysis data provided by NCEP/NCAR. The results indicate that the basic mode of global zonal-mean atmospheric circulation has significant interdecadal variability with a period of 20a. On the time scale about 20a, the change of zonal-mean temperature led the zonal-mean geopotential height by about 2 months, and led the zonal-mean flow by about 10 months. Furthermore, the change of zonal-mean geopotential height led the zonal-mean flow by about 8 months. The increase (decrease) of zonal-mean temperature caused the zonal-mean geopotential height descending (ascending) at high latitudes and ascending (descending) at middle and low latitudes; then further caused the zonal-mean westerly accelerating (decelerating) at middle and high latitudes and tropics, and westerly decelerating (accelerating) at polar regions and subtropics. On the 20a time scale, the signals of significant global warming from the end of the 1970s emerged firstly at the tropopause of the South Hemisphere, next at the lower troposphere over the South Hemisphere, and then the lower troposphere and the tropopause of the North Hemisphere.