A method for assembling a high-speed rotor, wherein the high-speed motor comprises a rotary shaft, first bearing, second bearing, an inner bushing and an outer bushing, wherein the inner bushing is of cylindrical shape, wherein the first bearing and the second bearing are of the same size; wherein, the said first bearing and second bearing are sleeved on the said rotary shaft at a certain interval, and the inner ring of the first bearing has one end in contact against a staircase section of the rotary shaft; wherein the said inner bushing is disposed between first bearing and second bearing and provides pre-tightening force onto the end faces of the outer rings of the first bearing and of the second bearing; wherein gluing grooves are disposed at the point where the said rotary shaft is joined to the first bearing and to the second bearing, and wherein the rotary shaft is glued securely to the first bearing and to the second bearing by the glue applied in the gluing grooves, such that once glued, the said inner bushing retains the pre-tightening force against the end faces of the outer rings of the first bearing and of the second bearing, the method comprising the following steps: I. Applying glue to the gluing groove of the rotary shaft corresponding to the first bearing, then fixing the first bearing in the corresponding area of the gluing groove, and making the inner ring of first bearing contact one end of the staircase section of the rotary shaft, maintaining the rotary shaft vertically to support the first bearing until the rotary shaft is securely glued to first bearing; II. Taking a standard bearing part with the same size as the second bearing and an outer bushing sleeved onto the outer ring of second bearing; vertically sleeving the outer bushing onto the standard bearing part, then placing the said inner bushing into the outer bushing such that it is pressed against the end face of the outer ring of the standard bearing part, applying glue on the outer ring face of second bearing, then placing the second bearing in the outer bushing, pressing the end face of the outer ring of second bearing in contact against the end face of the inner bushing, standing still until the outer ring face of second bearing is securely glued to the inner wall of the outer bushing; III. Applying glue to the outer ring face of first bearing and to the gluing groove of the rotary shaft corresponding to the second bearing as described in Step I, mating the outer bushing, second bearing, and inner bushing as described in Step II with the said rotary shaft and the first bearing, pressing the first bearing and the second bearing against both ends of the inner bushing, and inserting the first bearing into the outer bushing; keeping the staircase section of the rotary shaft vertically supporting the first bearing, the inner bushing and second bearing; before the glue in the gluing groove corresponding to the second bearing is hardened, sleeving a pre-tightening weight on top of the rotary shaft, the said pre-tightening weight applying a pre-tightening load on the end face of the inner ring of the said second bearing, until the first bearing and the second bearing are securely glued to the rotary shaft; and, after the glue has become hard, dismounting the pre-tightening weight so as to obtain the assembled high-speed rotor. I. Applying glue to the gluing groove of the rotary shaft corresponding to the first bearing, then fixing the first bearing in the corresponding area of the gluing groove, and making the inner ring of first bearing contact one end of the staircase section of the rotary shaft, maintaining the rotary shaft vertically to support the first bearing until the rotary shaft is securely glued to first bearing; II. Taking a standard bearing part with the same size as the second bearing and an outer bushing sleeved onto the outer ring of second bearing; vertically sleeving the outer bushing onto the standard bearing part, then placing the said inner bushing into the outer bushing such that it is pressed against the end face of the outer ring of the standard bearing part, applying glue on the outer ring face of second bearing, then placing the second bearing in the outer bushing, pressing the end face of the outer ring of second bearing in contact against the end face of the inner bushing, standing still until the outer ring face of second bearing is securely glued to the inner wall of the outer bushing; III. Applying glue to the outer ring face of first bearing and to the gluing groove of the rotary shaft corresponding to the second bearing as described in Step I, mating the outer bushing, second bearing, and inner bushing as described in Step II with the said rotary shaft and the first bearing, pressing the first bearing and the second bearing against both ends of the inner bushing, and inserting the first bearing into the outer bushing; keeping the staircase section of the rotary shaft vertically supporting the first bearing, the inner bushing and second bearing; before the glue in the gluing groove corresponding to the second bearing is hardened, sleeving a pre-tightening weight on top of the rotary shaft, the said pre-tightening weight applying a pre-tightening load on the end face of the inner ring of the said second bearing, until the first bearing and the second bearing are securely glued to the rotary shaft; and, after the glue has become hard, dismounting the pre-tightening weight so as to obtain the assembled high-speed rotor.