The utility model provides a voltage mutual inductor and a docking structure thereof. The voltage mutual inductor comprises a shell and a basin type insulator. The shell comprises a tank and an upper flange arranged on the top of the tank. The basin type insulator comprises a silica basin. The periphery of the top flange of the silica basin is coated with a metal flange. The metal flange is uniformly provided with steel wire screwed holes. The basin type insulator is fastened to the upper flange of the shell through screws and nuts passing through the steel wire screwed holes. According to the utility model, the metal flange provided with steel wire screwed holes and coated around the periphery of the top flange of the silica basin is directly docked with a GIS through screws and nuts, wherein no transition flange is adopted. Therefore, the product structure is simpler, while a transition flange, a sealing ring and other components are no longer needed. The voltage mutual inductor is lower in production cost so as to further improve economic benefits. During the docking process with a GIS, the docking structure is provided with one less sealing surface. Therefore, the leakage possibility is reduced and the sealing performance is improved. The docking structure further accords with the requirement of high performance.