The invention discloses an insulation shielding device of a high-voltage electrical appliance. The insulation shielding device comprises an installation plate and a shielding box, wherein the installation plate is fixedly connected to a bottom end of the shielding box, a plurality of installation posts are arranged on a surface of the installation plate, insulation rubber is arranged on surfaces of the installation posts, the shielding box is formed by connecting a plurality of shielding plates, prevention plates are arranged at connection positions of the shielding plates, each prevention plate is formed by vertically connecting two protection plates, each protection plate comprises a copper sheet and silicone rubber, the copper sheet is embedded into the silicone rubber, each shielding plate comprises a shielding layer and an insulation layer, a wiring hole is formed in a side surface of the shielding plate, a feed-through capacitor is arranged in the wiring hole and is conducted bya wire, and a plurality of shielding unit blocks are arranged in the shielding box. The whole insulation shielding device is convenient to install and disassemble, dual shielding is achieved by a modeof combining an internal part and an external part, the external interference can be effectively reduced, meanwhile, the insulation shielding device is good in insulation effect, the safety working of a high-voltage electrical appliance is ensured, and the insulation shielding device is worth promotion.