Abstract: In this paper,the waveletic analysis is used to focus on the dryness and wetness grades series in 500 years.The results show that the characters of xerasiumare ditterentin different levels,dry(waterlog ging)phase in upper level is made up of several dry (water logging)phase in lower level.The dynamic properties of climatic systemin different level have different characters.The singular points often degenerate to normal points when the level changes from lower to upper,vice versa,the normal points will evolute to singular points.The resultsal so show that the waterlogg ing semi-period is longer than dry semi-perid in generally,butithas different characterin different area.It also find there is phase difference between the south and the north.