The utility model provides a large workpiece continuous isokinetic stepped type sliding transportation device, comprising a stepped beam, an outer sliding track, an inner sliding track, two groups of jacking cylinders and two groups of horizontally arranged pushing cylinders. A sliding groove is recessed at the bottom of the stepped beam; the outer sliding track and the inner sliding track are arranged in the sliding groove; the two groups of jacking cylinders are vertically installed on the inner top surface of the sliding groove; the first group of jacking cylinders correspond to the outer sliding track, and the second group of jacking cylinders correspond to the inner sliding track; a horizontal distance is reserved between the rear end edge of each sliding track in the outer sliding track and the outer end of a piston rod of one jacking cylinder correspondingly close to the rear end edge; a slidable surface is reserved between the front end edge of each sliding track in the inner sliding track and an outer end of a piston rod of one jacking cylinder correspondingly close to the front end edge; the piston rods of the first group of pushing cylinders are connected with the rear end of the outer sliding track; the piston rods of the second group of pushing cylinders extend out and are connected with the rear end of the inner sliding track; and the cylinder bodies of the two groups of pushing cylinders are connected with the rear end of the stepped beam. After the stepped beam of the sliding transportation device jacks up a heavy load, the stepped beam can slide on the inner and outer sliding tracks alternately, and the sliding tracks alternately go forward in a stepped manner, so that the stepped beam and the heavy load can continuously go forward at a constant speed.