The invention discloses a protective high voltage circuit breaker-used insulator, which comprises a base. A sleeve-type insulator main body is fixedly connected onto the base; a plurality of insulated umbrella skirts are uniformly distributed on the outer wall of the insulator; an extending plastic thread opening is arranged at the top of the upper end of the insulator; a wire outgoing seat is screwed via the plastic thread opening; the wire outgoing seat is provided with a protective cover extending in an arc-shaped and bent mode towards the outer side of the upper end of the insulator along the outer edge; and the curved wall, connected with the insulator main body, on the inner side of the protective cover is provided with an insulated umbrella skirt. The protective high voltage circuit breaker-used insulator has the advantages that the structure is simple and reasonable; the mounting and the use are convenient; by adopting the design of arranging the protective cover covering the outer part on the insulator, the antifouling performance of the insulator can be effectively improved; the mechanical strength and the service life are improved; the insulator can be prevented from being influenced by a pollutant; the cooling performance and the insulated performance of the insulator are ensured; and the use safety of the insulator is ensured.