Abstract: For the specialty of cable topology in electric control system of truck crane, transmission-line model is built to study. The Juncture influence mode on signals transmission quality is analysed, and an equivalent model is constructed; Field-line coupling due to electromagnetic field is researched, and terminal response is calculated by establishing mathematical model which uses Agrawal theory. Final, validity of the equation is verified through simulating cable model of whole vehicle. The study provides reference for cable overall arrangement on truck crane.