The utility model relates to a protection device for a cable test, and specifically relates to a protection device for a cable withstand voltage test. The technical scheme is that, the periphery and an upper end of a housing made of insulation material are sealed, a lower end of the housing is provided with an opening, an isolation chamber with an opened bottom is formed inside the housing, and an insulation shield is arranged outside the opening at the lower end of the housing. The beneficial effects of the utility model are that, the protection device has the advantages of simple structure, convenient operation and low cost, and can effectively prevent the discharge of a test cable head and a switch cabinet, thereby preventing damages on equipment and ensuring the normal operation of the test.