With a view to the dual-polarization upgrade of CINRAD/SA weather radar in Jinan, the upgrade of key techniques such as WRSP (Weather Radar Signal Processor), frequency source of crystal oscillator, calibration technique, phase encoding technique, and new algorithm of signal processing technique is elaborated, and the performance of radar has improved. After upgrade, the sensitivity of receiver improves from -109 dBm to -113 dBm, the dynamic range of receiver from 89 dB to 101 dB, the output improvement factor of transmitter from 59.34 dB to 61.64 dB, the phase noise from 0.107° to 0.041°, the maximum value of actual ground clutter from 45.1 dB to 49.7 dB, and the range resolution from 1 000 m to 250 m. The upgrade of radar system improves the detection of weak signals, strengthens the recognition of electromagnetic interference and superrefraction, and enhances the resistance of ground clutter. Through altering antenna servo system from carbon brush slip ring to metal wire maintenance-free slip ring, the alarm rate of antenna's dynamic fault has reduced and the stability and reliability of servo system have increased. The consistency of the two channels of the upgraded dual-polarization radar is testified through the online calibration technique of CW and TS signals.