Climate effect caused by urbanization has been an indispensable artificial factor in research on regional climate change. Based on daily precipitation data, possible effects of precipitation on the development of three urban groups in east China are discussed. With three division methods (total population, population density and MODIS land cover), urban and rural stations are identified. The main findings are as follows. Climate effects caused by urbanization are different from place to place. In 1960-2009, the urbanization brought more precipitation to the Yangtze River Delta and Pearl River Delta city groups but had no obvious effect on the precipitation of the Beijing-Tianjin-Tangshan city group. The difference of precipitation is slight between urban and suburban areas in 1960-1979. It is more evident in 1980-2009 that urbanization has positive effects on precipitation in every city group. The difference of precipitation between urban and rural stations is sensitive to the ways of distinguishing rural from urban area, which may cause uncertainties in 1960-1979, while it is very different in 1980-2009 in which urbanization favors more precipitation in all city groups and their difference in precipitation is not sensitive to the division method.