German hot-dip galvanizing equipment for bridge surface treatment. The zinc bath has a large capacity and a depth of 2.5 meters. During hot dip galvanizing, the product will not contact the zinc slag deposited at the bottom of the bath, so it is not easy to produce zinc nodules; The whole system adopts multi-point fuel injection. The size of fuel injection is adjusted by computer to control the temperature. The temperature of zinc bath can be controlled within 460 ℃± 5 ℃. The product is heated stably and evenly during hot dip galvanizing without deformation. The thickness of zinc layer is controlled within 70-150 μ The components after hot-dip galvanizing are passivated, and the zinc layer surface forms an oxidation film with strong oxidation resistance, which can ensure a corrosion resistance life of 45 years.