The utility model belongs to the technical field of cooling equipment for isostatic pressure graphite production processes, in particular relates to a main shaft for a material airing machine, which aims to solve the problem that the main shaft for the material airing machine is easily loosened to cause collision between reamers and damage a speed reducer. The main shaft for the material airing machine comprises a left shaft head, a right shaft head and a hollow shaft, wherein the left and right shaft heads are in interference fit with the hollow shaft; a plurality of fixing pins are arranged at joints of the left and right shaft heads and the hollow shaft. According to the main shaft for the material airing machine, a pin connecting mode is adopted, so that the main shaft can be assembled and disassembled for multiple times, and equipment maintenance and repair are facilitated; the left and right shaft heads are solid, and cannot be provided with pinholes generally, internal thread taper pins with taper of 1:50 can be used for effectively solving the problem of difficulty in assembly and disassembly, and can be self-locked, so that compared with a conventional welding mode, the pin connecting mode has the advantages that the shaft heads, the hollow shaft and the fixing pins are uniform in stress and stable in connection, and the condition that the reamers and the speed reducer are damaged due to the loosening and slipping of the main shaft of the material airing machine is effectively avoided.