The invention discloses a conical phase locking carbon dioxide laser, and belongs to the fields of optical engineering and laser application. The conical carbon dioxide laser and axially-symmetric output beams are subjected to phase locking, and then convergent beams form intense coherent superposition, so the conical phase locking carbon dioxide laser has the laser processing efficiency and property sufficiently close to that of an axial flow carbon dioxide laser or even exceeding, and has the advantages in the aspects of device volume and use convenience. The conical phase locking carbon dioxide laser has good compactness the same as a cylindrical CO2 laser and a flat waveguide CO2 laser, the quality and the coherence of the output beams of the conical phase locking carbon dioxide laserare higher than those of the cylindrical CO2 laser, and the compactness and the output level quality of the conical phase locking carbon dioxide laser are higher than those of the flat waveguide device. After being processed by a convergence system, the output beams of the conical phase locking carbon dioxide laser can be conveniently applied to surface treatment, welding, cutting, perforating and the like of metal and nonmetallic materials; and the conical phase locking carbon dioxide laser can become an important device for laser processing.