Failure analysis and diagnostic techniques are important in the protection of large scale meteorological equipment and the reliable operation. According to the signal flow of CINRAD/SB antenna feeder system, through studying the fault diagnosis methods of the CINRAD antenna feeder system, the detection methods of antenna feeder system leakage and lighting faults, the fault diagnosis process of big antenna feeder systems loss, and six methods of fault location are summed up. According to the process of fault diagnosis and the spectrum analyzer method with external signal sources, the diagnosis and analysis are made of the typical example of weak radar echo intensity and reduced sensitivity resulted from circulation failure within the antenna pedestal. The results indicate that considering the instrument status at the radar site, through the process of fault diagnosis, the use of appropriate methods and techniques can achieve the quick location of antenna feeder system faults, so to repair radar failure timely.