The correctness and accuracy of observation data of Xband dual polarization Doppler weather radar are important prerequisites for subsequent application researches. The theoretical meaning of differential reflectivity, correlation coefficient, and differential phase shift are analyzed, and in combination with the experiences from several observation activities, the values of various polarimetric products in pure precipitation are studied and verified. Meanwhile, the polarimetric parameters for indicating the presence of hardware attenuation and faults are studied. The verification procedures of each parameter before observation are described. The TSG (Test Signal Generator) is used to ensure the consistency between horizontal and vertical channels.