The invention belongs to the field of the building construction, and provides a standard round tube combination support system. The system comprises a plurality of vertical support elements and a plurality oftransverse connecting pieces. Each vertical support element comprises a plurality of standard support units with the different heights. A plurality of standard support units with the different heightsare detachably connected in the height direction to form thecorresponding vertical support element. Each transverse connecting piece is detachably connected between every two adjacent support elements. In the support system, the standard support units of the different heights are selected to be detachably connected with each other according to the height needing to be supported by a building, and one vertical support element is formed. The adjacent vertical support elements are detachably connected with each other through the transverse connecting pieces to form a transverse support system, so that the stability of the entire support system is improved. Due to detachable connection of the standard support units, the convenience of the whole support system disassembling is improved, the detached standard support units are recycled, and the loss of materials is reduced.