The utility model discloses a detection tool for a bolt positioning hole of an embedded casing of a steel mould of a CRTS III type track board. The detection tool comprises a cylinder base, a flexible positioning cone and a set screw, wherein the cylinder base is cylinder-shaped; a prism base for fixing a prism is arranged in the center of the top of the cylinder base; a flexible positioning cone mounting slot is axially formed in the center of the bottom of the cylinder base; the bottom of a cone-shaped head of the flexible positioning cone is connected with an upper sleeve; the upper part of a flexible rod is movably inserted into the upper sleeve, and the lower part of the flexible rod is connected with a positioning cone base below the cylinder base through a lower sleeve; the positioning cone base is an inverted cone shape matched with the aperture of a positioning hole of the steel mould; and the set screw is locked with the flexible rod of the flexible positioning cone. With the adoption of the tool, the deviation of the positioning hole of the steel mould of the track board is converted into the deviation of the center of the prism on a device, so that the deviation of the positioning hole of the steel mould of the track board is accurately detected by a total station, and the detection efficiency is improved. The tool has the advantages that the structure is simple, the installation is convenient, and the positioning is accurate, thereby being widely applied to the field of detecting the positioning hole of the steel mould of the track board for a passenger special line.