It is proposed that in the multi-storey building with medium and large opening at the bottom (or small-span heavy load), priority should be given to the use of profiled concrete conversion beams and its profiled concrete structural system with large opening at the bottom, and for the high-rise and ultra-high-rise buildings with large opening at the bottom, the profiled concrete structure and prestressed profiled concrete hollow web truss conversion structural system can be used. To this end, the vertical load and low peripheral repeated horizontal load comparison tests of beam-type joist conversion structure with large bottom opening of section steel concrete and the corresponding structural model of ordinary reinforced concrete, as well as the vertical load and proposed dynamic comparison tests of pre-stressed section steel stacked hollow truss conversion structure with section steel concrete and the corresponding structural model of ordinary reinforced concrete are carried out, and some design suggestions for the structural system of section steel concrete bottom opening and conversion floor are put forward. Part of the design suggestions for the structural system of the conversion floor have been made, and fruitful results have been achieved. The research results of this paper have been successfully applied to three actual projects, which have achieved remarkable social and economic benefits.