As the core component of the radar transmitter, the klystron performance has a direct influence on the radar performance. But technicians are not willing to doubt Klystron’s performance because of the structural stability of the cavity body and the high cost. As a result, the performance of Klystron is usually not well judged. Some measures and suggestions to the problems generated in the process of constructing and troubleshooting of Radar are presented. Through tracking the fault alarm information of the Wanzhou CINRAD/SB radar, the faults generated are reviewed. In combination with the radar working environment and conditions when faults happened, the radar data are tested. By analyzing the function module based on the working principles of the transmitter, several reasons for the monotonously declining power of the radar transmitter are identified, and some countermeasures are given.