The invention relates to a slide rack device capable of enabling a power head to carry out damped oscillation, which consists of a slide rack (1), an oscillation barrel body (2), two constant velocity oil cylinders (3), a hollow shaft (5), a bearing (6), a joint bearing (7) and half shafts (8), wherein the centre of the oscillation barrel body is welded with the hollow shaft; shaft shoulders at both ends of the hollow shaft are respectively provided with a pair of the bearing and the joint shaft; both ends of the slide rack are welded with shaft bushes; the oscillation barrel body which is assembled through the haft shafts and the slide rack which is welded with the shaft bushes are connected together; piston ends of the two constant velocity oil cylinders which are symmetrically arranged into a shape like the inverted Chinese word figure 'ba' and form angles at 45 degrees with a power head (4) are connected with an extension supporting seat on the corresponding slide rack respectively through a pin shaft; cylinder bodies of the constant velocity oil cylinders are fixed on the extension supporting seat of the oscillation barrel body respectively through a bolt; and the lower part of the oscillation barrel body is hung with the power head so as to achieve the damped oscillation along the directions of the axial lines of the two half shafts. The slide rack device effectively relieves the impact force under wells, is favorable for the stress of a drill tool system, particularly improves the stress condition of the power head and prevents the deformation of a box body of the power head.