The utility model discloses a combined connecting shaft, including minor axis piece and major axis piece, be equipped with a plurality of connecting holes, locating hole and a draw -in groove on the minor axis piece, joint major axis piece in the draw -in groove, the correspondence locating hole is provided with locating piece and tight fit and in the locating hole, is equipped with the threaded holes and threaded counter bore who runs through on minor axis piece and the major axis piece respectively and passes through the bolt fastening on the major axis piece, be equipped with the connecting hole that runs through on the major axis piece, be equipped with a regular hexagon, with notch draw -in groove with it on the corresponding minor axis piece. The utility model discloses structural design is simple and ingenious, makes convenient to use, under the help of a plurality of locating pieces, uses the gim peg can connect two axles, convenient operation, and low in manufacturing cost does not have more maintenance cost moreover.