Based on North China summer precipitation and sea level pressure from 1900 to 1999 and NCEP mean monthly data from 1950 to 1999, the inter-decadal variational character of North China summer precipitation is studied in virtue of wavelet transformation.Which in turn is used to study the relation between inter-decadal variation of North China summer precipitation and general circulation over East Asia by means of composite analysis.The results show that North China summers underwent two rainy periods from the beginning of 1900 to the end of 1930s and from the end of 1940s to the end of 1970s,and two less rain ones from the end of 1930 to the end of 1940s and from the end of 1970s to the end of 1990s in the last century.When North China summer precipitation is less,the East Asian Monsoon will be weaker with accompanied features of positive anomaly of 500 hPa geo-potential height field over the Asia,the ridge and northern borderline of sub-high to the south,and existing blocking high over Baikal.While it is vice versa if North China summer precipitation is richer.