Based on the daily summer (June－August) precipitation at 91 stations in East China from 1961 to 2007 and NCEP/NCAR reanalysis data, five subdivisions of summer precipitation in East China are divided by using rotated empirical orthogonal function (REOF) method. They are subdivision I (Fujian－Jiangxi), subdivision II (South of the Yangtze River), subdivision III (the middle and lower reaches of the Yangtze River), subdivision IV (Huaihe River), and subdivision V (Yellow River－Huaihe River). Anomalies of summer rainfall in these five subdivisions change in different ways on interannual time scale. When the interannual rainfall in subdivision I is more (less) than normal, and other subdivisions’precipitation is less (more) than normal. Both the interdecadal variations and the interdecadal changes of interannual variabilities of the precipitation are remarkable. The maximum interannual variability occurs in the period that the precipitation is less than normal, or in the transition periods that the precipitation become more or less. The rainfall anomalies in different subdivisions are different. The area of Fujian－Jiangxi, the south of the Yangtze River, the middle and lower reaches of the Yangtze River have less rainfall, which is because an anomalous anticyclone causes moisture to diverge outward from these subdivisions. These anticyclonic circulation anomalies along with the abnormal diabatic cooling induce the anomalous descent of air, and henceforth lead to droughts in these subdivisions. In the region between the Yangtze River and the Huaihe River the divergent flow prevails. This divergent flow is caused by the divergence of the gear-coupled anomalous anticyclone north of the Huaihe River and anomalous cyclone south of the Yangtze River. This divergent flow transports the moisture outward from this region, reducing the precipitation there. In the Yellow River－the Huaihe River area, the divergent airflow exists between the anomalous anticyclone over the Mongolian Plateau and the abnormal cyclone over the western Pacific. It is also found that the five patterns of the summer rainfall anomalies are related to different teleconnections. Precipitation anomalies in Fujian and Jiangxi are influenced by Eurasia－Pacific (EUP) teleconnection. JJA (June－July－August) mean precipitation anomalies in the area south of the Yangtze River may be partly affected by East Asia－Pacific (EAP)/Pacific－Japan (PJ)/Pacific－North America (PNA) teleconnections. The JJA precipitation anomalies in the area along the Yangtze River are possibly influenced by East Atlantic (EA)/EAP teleconnection. It is apparently seen that the rainfall anomalies around the Huaihe River are influenced by EA/EUP and PJ/EAP teleconnections. The summer rainfall anomalies in the regions between the Yellow River and Huaihe River are likely to be influenced by the wave train perturbations propagating from the Mediterranean northeastward and influenced by AO (Arctic Oscillation). The summer rainfall anomalies in the five subdivisions are also found to be related to the potential vorticity anomalies in East Asia, anomalous activities of the South China Sea summer monsoon, the sea surface temperature anomalies in the Niño3 and Niño4 regions, and the variabilities of the western Pacific subtropical high.