The utility model provides an insulating bracket device for the withstand voltage test on parallel cables and mainly applied to the high-voltage test on transformer stations, which comprises at least two insulating brackets. The insulating brackets are connected together by means of connection wires. Each insulating bracket comprises a base, an upright bracket fixed on the base, and a clamping unit arranged at the top of the upright bracket. The upright brackets are high-voltage resistant and insulated and each clamping unit is composed of a fixed arm fixed onto the upright bracket, and a wire clamp arranged at one end of the fixed arm. The connection wires are connected with corresponding insulating brackets by means of the wire clamps. The wire clamps are also connected with test connection wires connected with to-be-tested phase wires. According to the technical scheme of the utility model, a plurality of insulating brackets are connected in series as a whole by means of connection wires, so that a plurality of identical phase wires can be simultaneously tested. That is, through the primary boosting process, a plurality of identical phase wires can be simultaneously tested. Therefore, the detection time is saved and the working efficiency is improved.