Abstract: When the leaky coaxial cable is used as a distributed sensor for indoor security intrusion detection in the internet of things and smart home, the simulation of long distance coupling can not be effectively simulated by full wave simulation software HFSS, and an equivalent circuit model is proposed. By using the parameter extraction software, we first extract the equivalent circuit model of the slot cell with single slotting. Then, with the help of transmission line theory, the transmission matrix of these 4 transmission lines is cascaded to get the transmission matrix of the whole leaky coaxial cable. The coupling between two leaky cables is considered, and an equivalent circuit model is proposed to characterize the coupling characteristics. The equivalent circuit model is built and simulated by using the commercial advanced design system(ADS) software. The experimental results show that the equivalent circuit models of two leaky cables are very consistent with the full wave simulation results, which can quickly simulate the long distance coupling leaky cable structure and greatly save the simulation time.