The invention relates to a double-bow cut-off device for detecting pantograph pressure of an engine. An installation rack is fixed at the inner side of a stand column at the outer side of a track, and is fixedly connected with the cut-off device through an insulative connecting rack. The concrete structure of the cut-off device is that: a working platform is fixedly connected with the connecting rack, the bottom of the working platform is fixedly provided with a transverse sliding rail; a transverse sliding seat is sleeved on the transverse sliding rail, a screw at the middle lower part of a vertical lifting rod is connected in a screw nut of the transverse sliding seat, the lower end of the lifting rod is connected with the outer ring of a bearing through a flange, the inner ring of the bearing is fixedly connected with the upper end part of a connecting rod; and the lower end of the connecting rod is connected with a longitudinal slide block, and a longitudinal slide block at the upper part of a contact network clip is sleeved on the longitudinal slide block. When contact pressure detection is carried out on more than two pantographs, the double-bow cut-off device can be utilized to eliminate the mutual interference between adjacent pantographs, thereby enabling the detection result to be more reliable and more accurate.