By analyzing the hardware structure and working principles of CTL713C Doppler weather radar digital receiving and processing system, this paper introduces the normal working conditions of the digital receiving and processing system based on the hardware status. The diagnosis of the CTL713C Doppler weather radar digital signal processing system is divided into signal processor and digital receiver, connected with three kinds of faults. The corresponding faults are identified according to terminal display and system hardware status indicator comprehensively. The diagnosis results are verified by a fault case of the Jiaozuo CTL713C Doppler weather radar digital signal processing system. The fault diagnosis methods and principles of the radar digital receiving and processing system are summarized, and the importance of the daily maintenance of the system hardware is discussed