The invention discloses an isolation switch rainproof cover which comprises a transmission connection rod passing through a high-voltage isolation switch mechanism case and a flange plate on the transmission connection rod. A rainproof cap is arranged on the transmission connection rod above the flange plate; the rainproof cap comprises a rainproof cap body both left and right parts can hold the transmission connection rod the rainproof cap comprises an umbrella-shaped cap, a bushing and a lower skirt; the transmission connection rod passes through the bushing and the umbrella-shaped cap; therainproof cap is fixed on the transmission connection rod by a hoop to synchronously rotate; a sleeve is arranged on the transmission connection rod below the flange plate; and the sleeve is arrangedon the high-voltage isolation switch mechanism case. The isolation switch rainproof cover is ingenious in structure; in an up-and-down staggered mode, rainwater cannot be accumulated in a large area on a top cover of the high-voltage isolation switch mechanism case so as to avoid corrosion and jamming of a transmission part, which are caused by rainwater pouring, and prolong the service life of arubber material sealing part; the spliced structure adopts a combined mode so as to facilitate disassembling and assembling; a material secondary recovery rate is high; and the isolation switch rainproof cover is an efficient and reliable outdoor high-voltage electrical equipment protection device.