By investigating distribution and change of rainfall from 1961 to 2000 with analyses of empirial orthogonal function

wavelet and fractal dimension

the typical drought and waterlog were confirmed. Results showed that the amount of rainfall increased from the west to the east in the Loess Plateau in waterlog year

and from the north to the south in drought year.The fractal dimension of waterlog rainfall frequency was bigger than that of drought year.The interval of rainfall was more complicated in the waterlog year than in drought year.The rainfall frequency had differences between drought and waterlog year.The short variation period was dominant in waterlog year

and long period in drought year.The power of distributed rainfall by mountains was stronger in waterlog year than in drought year.Heavy rain frequency was much more variable in waterlog year than drought year.