The invention relates to a construction method of beam transportation through the transiting of a railway. The construction method comprises the following steps of prefabricating a steel platform; paving protecting steel plates; casting a concrete temporary abutment wall; subsequently connecting beam transportation roads on two sides; paving a square timber wood panel structure; emplacing the traction of the steel platform; paving sleeper piers in gaps of the platform, and placing bevel steel shores at two ends; enabling a beam transportation vehicle to pass through the steel platform; disassembling the steel platform; disassembling the sleeper and the bevel steel shores; disassembling the square timber board; disassembling the concrete temporary abutment wall; disassembling the protectingsteel plates; restoring lines and the like. According to the construction method of the beam transportation through the transiting of the railway disclosed by the invention, the difficult problem that during the construction of a city bridge, a beam transportation vehicle can safely and quickly pass through a conventional railway when the influence of the operation of the conventional railway isreduced. The construction method disclosed by the invention adopts a series of technical measures, so that the safety of tracks of the conventional railway and relative facilities in the whole construction process is guaranteed; the transportation safety of the beam transportation vehicle is guaranteed; the construction risk is reduced; the investment cost is saved; and the beam transportation efficiency is improved.