In a closed domain space, various communication equipment and instruments are equipped, with a large amount of data interaction and poor transmission conditions. Leaky coaxial cables are usually adopted as the communication solution. Therefore, this study focuses on the analysis of the radiation characteristics and channel features of leaky coaxial cables in a closed domain space. Leaky coaxial cables feature uniform signal coverage, low attenuation, high coupling coefficient, no blind spots, less electromagnetic pollution and easy implementation. They are widely used in closed and semi-closed spaces where signals are hard to reach. The main application scenarios include regional monitoring systems and mobile communication systems.