By using ECWMF and NCEP/NCAR monthly mean reanalysis data(from September 1957 to August 2002), characteristics of interannual potential predictability of SLP, 500 hPa geopotential height, 200 hPa zonal wind and 850 hPa meridional wind in winter and summer are analyzed respectively.The results show that the potential predictability is high in the tropics, especially the equatorial area and eastern Pacific.In contrast, the potential predictability is relatively low over the middle and high latitudinal areas.After comparing the differences between these two sets of reanalysis data, we find that the difference in the Southern Hemisphere is more obvious than that in the Northern Hemisphere, especially around the South Pole.The difference in low-level variables is larger than those in middle-and high-level variables.There exists some potential predictability in East Asian in both winter and summer.East Asian winter monsoon described by all the variables in both two sets of reanalysis data has high potential predictability with little difference.Only the East Asian summer monsoon described by 500 hPa geopotential height shows high potential predictability with little difference.There are obvious differences in East Asian summer monsoon's potential predictability with low-level variables including SLP and 850 hPa meridional wind between the two sets of reanalysis data.