The invention relates to the technical field of bridge and building construction, in particular to an assembling type heavy steel tube supporting device. The assembling type heavy steel tube supporting device comprises a plurality of supporting sections sequentially spliced in the vertical direction, the supporting sections comprise a plurality of vertical heavy steel tubes, and the number of the heavy steel tubes meets the requirement that the supporting device has the sufficient supporting strength in the vertical direction. The heavy steel tubes are spaced by a proper distance, so that the supporting device has the enough stability in the horizontal direction, connecting rods are connected between the heavy steel tubes, the supporting sections are detachably connected, the connecting rods and the heavy steel tubes are detachably connected, and the connecting rods are detachably connected. In the scheme, the assembling difficulty of the supporting device is lowered, and the supporting device is convenient to assemble and disassemble so that the supporting device can be repeatedly used, and construction cost can be lowered.