Using the NCEP/NCAR reanalyzing data and themonthly rainfall data at 160 stations in China from 1958 to 2000,this paper analyzes the influence of the variation of AAO in April and May on summer precipitation in the east of China.The results are as following:the correlation coefficient,on interannual scale,between averaged AAO index over April-May and June-July rainfall in the Yangtze River is 0.31,which is significant at the 95% confidence level.When the April-May AAO is stronger,the subsequent June-July precipitation in the Yangtze River will increases,and v.v..The change of AAO in April and May will impact the June-July intensity and position of the northwest Pacific subtropical high,thus affecting the south-north position of the summermonsoon rainbelt in China.