Based on the monthly rainfall data at 160 stations in China during 1951—2005,the spatial-temporal variations of summer rainfall anomaly at 17 stations in North China are studied,and the atmospheric circulation factors influencing the rainfall anomaly over North China are discussed.Results show that the total summer rainfall tendency of North China decreases significantly during 1951—2005 with the interannual variations of quasi-three,quasi-six,quasi-eight years and the interdecadal variation of 17—19 years....