The invention discloses a clamping device for an electrical contact of an isolating switch, comprising: a base, a first clamping part and a second clamping part; the first clamping part comprises: two first telescopic rods, two second Two telescopic rods, two third telescopic rods, rollers, two first rotating shafts, two second rotating shafts and two rollers, the second clamping part includes: two fourth telescopic rods, two fifth Telescoping rod, third hinge, fourth hinge and two clips. The present invention adapts to electrical contacts of different sizes and radians by adjusting the components of the first clamping part and the second clamping part before and during spraying. Adjust the parts of the first clamping part and the second clamping part to move the electrical contacts, adjust the spraying position, angle and distance, and maintain the plane spraying of the electrical contacts, so as to improve the deposition efficiency of spraying, the quality of the deposited layer and the deposition thickness, no need to move the spraying device, greatly reducing the workload, and the operation is simple and convenient.