The Wen-Tang river extra large bridge in Shuo-Huang railway was taken as an example, by using an axle box suspension truck model, coupling motion equations of vehicle-bridge system of heavy haul were built up. By using the iteration, the bridge-vehicle coupling vibration analysis program of heavy haul railway was established. The influence of a variety of dynamic performance indicators for the speed of heavy-haul train over simply supported girder bridges were analyzed by the simulation calculation and field test. With the inspection specification of the existing railway bridge, the adaptability of increasing speed of existing heavy haul railway bridges were analyzed, the highest speed of heavy-duty train through the railway bridges was put forward the proposal.