By using the DEM data,quickbird materials and Gis software in Xifeng district,the paper analyzed the channel property so as to get the feature required by rainwater resources computing. We chosed the storm frequency of 1%-99% to analyze the characteristics of channel flood, and used typical year method and single rainstorm analysis method to normalize the storm frequency and precipitation frequency. Then the paper calculated the total amount of typical year and flood peak flow of single rainstorm precipitation.The result indicated that when rainfall frequency was 25%, the rainwater resources utilization amount is 39.70 million m3; when rainfall frequency was 50%, the rainwater resources utilization amount was 38.43 million m3; when rainfall frequency was 75%, the rainwater resources utilization amount was 16.42 million m3;when rainfall frequency was 95%, the rainwater resources utilization amount was 20.09 million m3.Meanwhile，the paper calculated the collected amount of the channel rainwater resources in different precipitation guaranteed rates of different towns. The top three towns of channel rainwater resources are Shen She, Dong Zhi and Hou Guanzhai. The results showed that the basic trend of channel rainwater resources quantity of different precipitation guarantee rate in Xifeng district was high guaranteed rate corresponding to less rainwater resources quantity, and low guaranteed rate corresponding to more rainwater resources quantity, which were consistenting with the overall trend of precipitation guaranteed rate. But the flood frequency was not synchronized with the rainfall frequency. when the precipitation frequency in drought year was low, there may be greater flood frequency.Therefore,it was very important to use rainwater resourcest in drought years.