The channel characteristics were obtained by analyzing the DEM data and quickbird images of Xifeng District, and the characteristics of the channel floods with different frequencies were also analyzed. Typical year method and single rainstorm analysis method were used to normalize the storm frequency and precipitation frequency, and make a relation between the single rainstorm precipitation over 20mm in different precipitation frequencies typical years and the baseline storm amount, so as to calculate the total amount of channel rainwater and single rainfall peak flow. The results show that high precipitation frequency has less rainwater resources quantity, and low precipitation frequency has more rainwater resources quantity. However, the flood frequency is not synchronized with the rainfall frequency, and when the low precipitation frequency in drought years, there may be greater flood frequency, thus, the use of rainwater resources is particularly important in drought years.