The invention relates to a three-branched chain parallel external fixation device adopting annular adjustment. The three-branched chain parallel external fixation device comprises a near end ring, a far end ring, a hook joint, a spherical hinge, telescopic branched chains, annular guide rails, adjusting hand wheels, adjusting knobs, kirschner wires and a locking wire chucks. Through kirschner wires, the near end ring and the far end ring of the external fixation device are perpendicularly and rigidly fixed to a deformable bone separately, the annular guide rails are arranged on the near end ring and the far end ring respectively, the adjusting hand wheels are connected with sliding blocks on the annular guide rails, the adjusting knobs are installed on the telescopic branched chains, through the adjusting hand wheels and the adjusting knobs, the sliding blocks move around the annular guide rails, meanwhile, the telescopic branched chains extend or retract, and therefore the three-branched parallel external fixation device realizes 6-DOF movement and can correct any spatial three-dimensional bone deformity. The three-branched chain design is adopted, the annular guide rails are arranged, a 3-PUPS parallel structure is formed, and the three-branched chain parallel external fixation device has the advantages of being simple in structure, large in work space and flexible to operate, being provided with a few movement chains, and not being interfered easily.