Aiming at the requirement of regular field testing and fault diagnosis of the electrical characteristics of the airborne GJB289A bus network, the GJB289A bus network is modeled and simulated by the ADS (Advanced Design System) software, and the typical electrical fault characteristics of the GJB289A bus network are studied. According to the distribution parameters of transformer and terminal resistance, and the lossy coupling transmission line model of the GJB289A bus system, a two-port network model containing two coupling transformers is constructed in the ADS software, and the effectiveness of the simulation model based on distributed parameters is verified by theoretical derivation and laboratory test comparison analysis. Based on the distributed parameter model of two port network, the characteristic waveforms and parameters of typical electrical fault types are analyzed and sorted out to realize the rapid judgment of typical electrical faults. Combined with the topology, physical size and distribution parameters of the actual GJB289A bus network, the accurate waveforms of the test port and the characteristic parameters of typical electrical faults can be simulated by using this method, which provides technical support for optimal design of bus detection equipment and the health management of the bus network state.