The ensemble experiments composed of 8 members have been preformed from 1979 to 2000 by the National Center for Atmospheric Research (NCAR) Community Atmosphere Model Version 3(CAM3).Each experiment is forced by the observed sea surface temperature(SST).The analysis of variance is applied to investigate the potential predictability of East Asian summer atmospheric circulation.Results show that the potential predictability of summer sea level pressure is low in East Asia as a whole, and is high(low) in Southeast(Northwest) China.The potential predictability of East Asian summer 850 hPa zonal wind, tropospheric temperature averaged from 500 to 200 hPa, and 500 hPa geopotential height is higher in low latitudes than that in mid-high latitudes.The potential predictability of summer 500 hPa geopotential height is high, which is greater than 0.5 in the East Asia, especially larger than 0.7 over South China.It is found that the potential predictability of East Asian summer 500 hPa geopotential height exhibits distinct interannual variability, which is closely related with sea surface temperature anomaly (SST) in South China Sea in summer.Compared with that in the normal SST years, the potential predictability of East Asian summer 500 hPa geopotential height is higher in the warmer or colder SST years.