The invention discloses a PDC bit port assembling device which comprises a movable torsion rod, a torsion transmission rod, a torsion transmission base, limiting bosses and an insertion rod. A connecting hole is formed in the upper end of the torsion transmission rod, and the lower end face of the torsion transmission rod is welded to the upper end face of the torsion transmission base in a centered manner. The insertion rod is welded to the lower end face of the torsion transmission base in a centered manner. The torsion transmission base and the insertion rod are solid cylinders, and the diameter of the insertion rod is smaller than that of the torsion transmission base. The limiting bosses are evenly welded to the periphery of the lower end face of the torsion transmission base, and thelimiting bosses are evenly distributed around the outer side of the insertion rod. The movable torsion rod is arranged in the connecting hole in the upper end of the torsion transmission rod in a penetrating manner. By means of the PDC bit port assembling device, the problem that the center axis of the bit port assembling device does not coincide with the center axis of a bit port body, consequently the rotating torsion transmitted to a groove in the upper end face of the bit port body is uneven, and the port body is damaged is solved, the repeated utilization rate of the bit port body is increased, and the efficiency of the work of mounting and demounting or taking out the bit port body is improved.