The invention relates to the technical field of petroleum drilling, and relates to an under-balanced high-pressure gas injection pressure relief manifold device which comprises an air injection pipeline, a first pressure relief pipeline, a second pressure relief pipeline and an operation control box. The air injection pipeline comprises an air inlet section and an air outlet section, a main control valve is connected between the air inlet section and the air outlet section, one end of the first pressure relief pipeline is arranged on the air inlet section and is in a tee structure with the airinlet section, and one end of the second pressure relief pipeline is arranged on the air outlet section and is in a tee structure with the air outlet section. According to the under-balanced high-pressure gas injection pressure relief manifold device, the opening and closing of a main control valve, a first auxiliary control valve and a second auxiliary control valve are remotely controlled through the operation control box, so that the automatic operation of gas injection and pressure relief is realized, the labor intensification of workers is reduced, and the operation risk of a high-pressure area is further avoided.