Provided is a tool for adjusting balance of a walking beam type pumping unit well. The tool comprises a gear (1), a screw rod (2), a nut (3), an H-shaped base (4) and a ratchet handle (5). The tool is characterized in that a through hole is formed in the upper portion of the H-shaped base (4), the screw rod (2) penetrates through a center hole of the gear (1) to be screwed with the nut (3) through the through hole in the H-shaped base (4), the screw rod (2) is in key connection with the through hole in the H-shaped base (4), and a wrench arranged on the lower portion of the ratchet handle (5) is matched with the end of the screw rod (2). The tool for adjusting the balance of the walking beam type pumping unit well is novel in structure and safe in operation, adjustment of a balance block of the walking beam type pumping unit well is convenient, rapid, time-saving and labor-saving, working intensity of workers on the post is reduced, well stopping time is shortened, oil extraction time rate is improved, and crude oil yield is increased.