At present, greentel Fiber Optic Splice Closure has a wide range of applications, but the insulation problem of the fiber optic splice closure has always been a big problem, and the appropriate choice is made based on the dielectric properties and the degree of plasticity of the material itself. Therefore, the structure, material, and surface condition of the insulation also have a great influence on the withstand voltage strength performance of the fiber optic splice closure. Reasonable insulation material is the fundamental guarantee for withstand high voltage DC breakdown. Therefore, the structure, material, and surface condition of the insulation also have a great influence on the withstand voltage strength performance of the fiber optic splice closure. In order to improve the withstand voltage performance of the fiber optic splice closure, better insulating materials must be used to increase the surface finish and reduce the curvature between the insulator and the pole and pole and between the pole and the ground. With other parameters being the same, this situation can be increased by at least 100%. The fiber optic splice closure is an indispensable and important part of the optical cable communication line. The main function is to realize the connection of the optical fiber cable, and at the same time, to ensure the grounding function of the fiber optic splice closure, the internal grounding device and the grounding portion of the optical cable must be electrically connected, and the metal component of the fiber optic splice closure and the grounding device and the cable reinforcing core are ensured. Insulate from each other to avoid adverse effects from the environment on the cable splice closures. Since the environment in which fiber optic splice closures are used is basically outdoor, their use environment may be buried, overhead, or pipeline. Therefore, higher requirements are placed on the design of the fixing and grounding devices of the fiber optic splice closure and the insulating materials used.