The invention discloses an aluminum alloy polishing solution and a polishing method and equipment. The aluminum alloy polishing solution comprises a saturated sodium chloride aqueous solution, a flame retardant which accounts for 1 to 5 percent of the total weight of sodium chloride, and absolute ethyl alcohol which accounts for 2 to 10 percent of the total volume of the aluminum alloy polishing solution. The aluminum alloy polishing solution, the polishing method and equipment overcome multiple defects of the prior art, realize the advantages that raw materials are easy to obtain, the polishing depth is uniform and the polishing efficiency is high, can be widely used for polishing of aluminum alloys, and ensure the accuracy of X-ray nondestructive measurement of the residual stress of welding of the aluminum alloys.