This invention presents a modified reinforced concrete structure, which has a steel structure composed of a beam steel box unit, column steel box unit, and beam-column joint steel box unit with lap jointing reinforced steels. The side plate and/or end plate of the steel box has through holes for concrete flowing therebetween. In this way, the workability of concrete grouting and tamping are improved, and the phenomena of hive, segregation, or floating can be avoided. It can also enhance the performance of beam-column joints (e.g. with better confinement ability, etc.). Applying the invention, the efficiency and accuracy of constructing beam-column joints can be increased, and in addition to better ensure the structural safety, it can also reduce construction manpower and schedule.