The invention discloses a circular laser tube bracket with the adjustable caliber and position. The circular laser tube bracket comprises a V-shaped support mechanism, a lifting mechanism and a lateral movement mechanism. The V-shaped support mechanism is installed at the upper part of the lateral movement mechanism by the lifting mechanism. The circular laser tube bracket having the long servicelife is suitable for circular laser tubes with different tube diameters. Automatic centering of the circular laser tube is realized, so that the trouble of bracket replacement is saved; and the circular laser tube is convenient to dismount. Adjustment of the circular laser tube in five degree-of-freedom directions is realized. After mounting of the circular laser tube, the circular laser tube is fastened firstly and then adjustment of the degree-of-freedom directions is carried out to realize overlapping of the central axis of the circular laser tube and the laser beam, thereby reaching the optimal position of the circular laser tube. The circular laser tube bracket having the high redundancy is capable of realizing caliber and position adjustment of the circular laser tube bracket in different work conditions and thus is worthy of promotion and popularization.