Abstract: Based on theoretical design, numerical simulation and on-site measured data and feedback, the application of slot impact jet in post-palvanizing cooling design is analyzed, and calculation formulas for structural parameters and air box pressure are summarized, which can accurately select the fan type. The research findings provide reference for engineering design. At the same time, under the same energy consumption, the air box structure is optimized to achieve the best cooling capacity. A fitting formula of the optimal structural parameters is provided, which provides a convenient and feasible reference scheme for engineering application promotion.