The invention discloses a ray inspection tool for a rudder of an airplane. The ray inspection tool comprises a fixed frame, an inspection equipment bracket, a ray machine head, a longitudinal sliding bearing platform and a base plate, wherein moving wheels are mounted at the lower end of the base plate, the ray machine head is mounted at the upper end of the inspection equipment bracket through the fixed frame, the base plate is located right below the inspection equipment bracket, and the longitudinal sliding bearing platform is mounted right above the base plate. The ray inspection tool has the advantages of reasonable structural design, convenience in use and the like. The X-ray flaw detection efficiency of the rudder, the transillumination focal length, the transillumination range, the movement convenience between the ray machine head and the rudder and the flaw detection quality requirements are comprehensively considered. After the ray inspection tool is put into use, the ray inspection work efficiency of the rudder of the airplane can be greatly improved by 50%, and meanwhile, the moving number of times of the rudder can be reduced, so that the risk of damaging the rudder by collision is lowered.