In order to add new MeiYu season sample in the MidLower Reaches of t he Changjiang River, the daily data of reanalysis from NCEP/NCAR and the precipitation observation of 5 stations i n the MidLower Reaches of the Changjiang River are used and some routine met hods based on circulation consideration are adopted to diagnose the characteristic parameter of summer MeiYu period in the MidLower Reaches of the Changjiang River in 2006, and to discuss the relationship between MeiYu season and summer monsoon in that year. The result shows that it is reasonable to ensure th at the beginning and ending MeiYu season in the MidLower Reaches of the C hangjiang River are the 5th pentad of June and the 4th pentad of July respective ly, also the total MeiYu precipitation of 2006 is below the normal due to the weaker Indomonsoon and east Asia mons oon (including summer the South China Sea monsoon and summer subtropical monsoon) o f that season.