The invention discloses a gear backlash adjusting structure and an adjusting method thereof, and belongs to the technical field of gear backlash adjusting structures and adjusting methods thereof. Thetechnical problem to be solved is to provide the improvement of the gear backlash adjusting structure. According to the technical scheme adopted for solving the technical problem, the gear backlash adjusting structure comprises a platform, a
slewing bearing mounting hole and an adjusting
flange mounting hole are formed in the platform, a
slewing bearing is fixedly connected to the slewing bearingmounting hole, an adjusting
flange is fixedly connected to the adjusting
flange mounting hole, a transition flange is arranged between the
slewing bearing and the platform, a motor and a speed
reducer are fixedly connected to the lower portion of the adjusting flange, a
pinion is arranged on the adjusting flange, the center of the
pinion does not coincide with the center of the adjusting flange,the
pinion is engaged with the slewing bearing, a spline of the pinion is fixed to the shaft end of the speed
reducer, and a notch is formed in the adjusting flange. The gear backlash adjusting structure and the adjusting method thereof are applied to gear backlash adjustment of
engineering vehicles.