Abstract: In order to improve the efficiency and visualisation level of airborne cable fault diagnosis in aviation system, this paper researches on airborne cable fault diagnosis technology and fault visualisation technology. In terms of fault diagnosis, this paper designs an airborne cable fault diagnosis system based on spread spectrum time domain reflection technology; at the same time, in order to solve the signal reflection problem caused by the mismatch between the impedance of the diagnosis system and that of the cable to be tested, the system also introduces the impedance measurement and impedance matching function, which adopts the automatic balancing bridge technology to measure the characteristic impedance of the cable and realises the impedance matching through the impedance matching network; and experiments show that the system is able to complete the impedance measurement and fault diagnosis well. In terms of fault visualisation, this paper uses CATIA software to construct a digital 3D model of the airborne cable and develops an airborne cable fault visualisation system based on CATIA secondary development technology, which realises the visual presentation of fault diagnosis results.