The meteorological and hydrological data in the Songhuajiang and Nenjiang area were used to discuss the effect of precipitation on the change of the water level.The conclusion is that there is a close relationship between the water level in floodwater season and the precipitation over the Songhuajiang and Nenjiang area.The severe flood in the summer of 1998 was caused by more precipitation over the Nenjiang river.The daily change of water level is closely related to the upstream water level and the precipitation over the near region.