Composite insulator is the abbreviation of rod suspension type silicone rubber insulator, which is the key product for transmission line promotion and application. Compared with the traditional porcelain insulator and tempered glass insulator, the composite insulator has the advantages of light weight, small volume, convenient transportation and installation, high mechanical strength and good pollution resistance. At the same time, it can avoid cleaning and preventive testing during operation, which can effectively reduce pollution flashover accidents, and is especially suitable for urban power grids and polluted areas.