The present invention relates to a voltage grading shield and a disconnecting switch. The voltage grading shield comprises an upper shield and a lower shield, wherein one of the upper shield and the lower shield is provided with an internal spigot structure and the other can be inserted into the internal spigot structure to realize the fastening of the upper and lower shields. A connecting hole iscorrespondingly arranged in the wall on which the upper and lower shields are overlapped; the upper and lower shields are detachably connected through a connecting member mounted in the correspondingconnecting hole; after the upper and lower shields are fastened and connected, the whole is in a mushroom shape; the bottom of the lower shield is provided with a through hole for extending a post insulator thereinto; and a connection structure for directly or indirectly connecting the post insulator is arranged in the lower shield. The voltage grading shield in the present invention can accurately locate the upper and lower shields through the internal spigot structure; the connecting member can be placed from the outer side and used for connecting the upper and lower shields; the assembly process is simple and convenient; the installation difficulty is reduced; and the installation efficiency is improved.