The utility model discloses a preventive test device for an insulated safety tool. The preventive test device comprises a square frame and six hooks, of which two are made of insulating material, and the rest are made of conductive material. The set of hooks made of insulating materials are suspended between the two sets of hooks made of conductive materials. The preventive test device further comprises a pressurizing terminal and grounding terminals, wherein the pressurizing terminal is suspended to the lower terminals of the hooks made of insulating materials, and the grounding terminals are suspended to the lower terminals of the hooks made of conductive materials. More than one arc opening grooves are arranged on the edges of the pressurizing terminal and the grounding terminals facing upwards, and the arc opening grooves are provided with a support and a movable bayonet. The preventive test device can be adjusted according to the size of a test workshop, and the test voltage is reduced to voltage suitable for safe test distance. The pressurizing terminal and two grounding terminals are flexibly suspended to different positions of a square frame for testing, and the number of the pressurizing terminal or the grounding terminal and the hook can be increased as required to meet the requirement for samples of more specification.