Arm support pulley block assembling tool

The utility model provides a cantilever crane pulley block assembling tool, and relates to the technical field of crane manufacturing. The cantilever crane pulley block assembling tool is used for assembling a pulley block on a cantilever crane of a crane and comprises a positioning frame and a pull-back oil cylinder. And the positioning frame is used for positioning the pulley blocks to ensure the coaxiality of the pulleys in the pulley blocks. A cylinder body of the pull-back oil cylinder is used for being arranged on the first side of the pulley block, a piston rod of the pull-back oil cylinder penetrates through a shaft hole and an arm support hole of the pulley block to be connected with a pulley shaft located on the second side of the pulley block, and the pulley shaft can be pulledin the direction close to the first side to penetrate through the shaft hole and the arm support hole, and the first side is opposite to the second side. The cantilever crane pulley block assembling tool can reduce damage to