The clutter echo affects the measurement of rainfall rate and hydrologic forecast with dual linear polarization radar.In this paper,we have studied the range of reflectivity Z_H and differential reflectivity Z_DR and their spatial distributions in rainfall and clutter regions.The Z_DR of rainfall is positive and increases with increase of Z_H.This phenomena proved that there are more large particles in the region with great Z_H.But for the clutter,the values of Z_DR are positive or negative,and there is no obvious relationship between Z_H and Z_DR,the spatial variability of Z_H and Z_DR is greater than rainfall area.Based on these research,we have developed a model of discrimination between rainfall and clutter.The results of test is satisfied.This work is a new method reducing the effects of clutters on the dual linear polarization radar measurement,it can improved the results of measuring rainfall and hydrologic forecast.