Dynamic focusing device used on laser light path system

The utility model relates to a dynamic focusing device used on a laser light path system, which comprises a bottom plate (8), a galvanometer type vibrating mirror motor (1) positioned above the bottom plate, a support (2) used for fixing the galvanometer type vibrating mirror motor, and a linear guide rail (7) mounted on the bottom plate; at least one lens (5) is fixedly mounted in a lens support (6); a light limiting device (3) is arranged in front of the lens (5); the center of the upper limit unthreaded hole of the light limiting device (3) and the center of the lens (5) are positioned in the same straight line; and the lens support (6) used for fixing the lens is connected with the galvanometer type vibrating mirror motor (1) through a crank gear (4) and fixed on the slide block of the linear guide rail (7). The utility model solves the problem of changeless focal length of the lens in the prior art, enables diameters of laser focal spots within a full-frame scanning area to be even, and ensures the consi