Based on the summer(June—August) precipitation data from 11 stations over Yangtze-Huaihe valley from 1951 to 2010,the northern hemisphere mean sea level pressure field data provided by NCAR and the west Pacific subtropical high indexes,the interannual variability of the quasi-biennial oscillation(QBO) of the summer precipitation and its relationship with east Asia summer monsoon and west Pacific subtropical high were discussed by using Morlet wavelet transform,cross wavelet transform and correlation analysis method.The results showed that QBO component was very important in the interannual oscillation of summer precipitation field in Yangtze-Huaihe region,which experienced a course of changing from strong to weak,and then to strong again.In addition,the contemporaneous correlation between precipitation and QBO of summer monsoon intensity as well as subtropical high ridge was good.Their mutual impact was also shown in the interannual scale and there was obvious lagged and leading correlation respectively in four-year and one-year scales.