Abstract: The effect of Nb addition on the microstructure and mechanical properties of Ti-IF steel was discussed according to the facilities of the continuous hot-dip galvanizing line at PZH Steel, as well as the influence of annealing temperature and skin-passed reduction on extra deep drawing skin-passed hot-dip IF steel sheet. The grain refinement of Nb is applied to control the balance of n and r-value of the sheets, and DX54D grade skin-passed hot dip galvanized sheet with excellent mechanical properties has been developed according to DIN EN 10142 standard. This product is widely used to make panel of air conditioner as a substitute of deep drawing electrogalvanizing steel sheet.