Abstract: In order to efficiently analyze crosstalk of coaxial cable bundles, a new equivalent method for simplifying the simulation model of coaxial cable bundles is proposed. This method divides the process of simplifying the cable bundle into two steps. First, in order to solve the problem that the braided shielding of the coaxial cable is too complicated to simulate, the internal and external transmission line (IETL) transfer matrix is used to simplify the coaxial cable, and the coaxial cable bundle is converted into a 3D cable bundle model composed of single core wires. Then, the equivalent cable bundle method (ECBM) is used to further simplify the full single-core cable bundle by reducing the number of single-core wires. The simplified model can be used for the internal crosstalk simulation of the cable bundle in any 3D electromagnetic simulation software without considering the limitations of the equivalent circuit method based on the classic multiconductor transmission line (MTL) theory. The proposed method and the equivalent circuit method are respectively applied to the simulation of the internal crosstalk of the cable bundle, and the simulation results are in good agreement, which shows that the method proposed in the article is accurate, and can be used to efficiently analyze the internal crosstalk of coaxial cable bundles.