The invention provides a construction method used for antique building concrete bearing components by combining a rear welding mounting technology. The construction method is unique. According to theconstruction method, owing to the fact that short columns above beams and square columns are a lot, steel bars at beam-column joints are dense, and additionally the upper portions and the lower portions of cylinders at the beam-column joints are unequal in diameter, although the columns form an independent system, the columns are still not easy to construct to the tops. Thus, the columns need to be innovatively divided into four construction sections of the front body sections, the column head sections, the bucket arch sections and the column top sections, and by combining the construction characteristics of antique buildings, various normal-shaped molds and special-shaped molds are developed and applied for combination construction. The formed cylinders meet the requirement of clear water, and additionally mature painting technology treatment is adopted, so that the artistic effect which is the same as a wooden structure is achieved. According to the construction method, the construction working procedure is simplified, the construction working period is shortened, the construction cost is saved, and therefore the integrality of the cylinders is improved.