The quality of the rotary joints greatly influences the consistency of the dual channel of polarimetric radar. Actually, the bias of 〖WTBX〗Z〖WTBZ〗dr varies with azimuth and elevation because the rotary joints are asymmetric in structure due to the production process, and it affects the accuracy of using radar data for quantitative precipitation estimation and hydrometeor classification. The CW (Continuous Wave) signals of the Cband dualpolarization radar of the Nanjing University of Information Science and Technology were used to detect the measurement errors caused by the rotary joint for azimuth and elevation. The results show that the rotary joints have some influence on the measurement results of 〖WTBX〗Z〖WTBZ〗dr of dual polarization weather radar, and it can be seen that the effect is relatively stable, in combined with the results of VCP and RHI, which provides a basis for the correction of the errors caused by rotary joints in using radar data.