The invention relates to an application of a normal paraffin isomerization catalyst. The normal paraffin isomerization catalyst is used for an isomerization reaction of C4-C8 normal paraffin. According to the application, a preparation method of the normal paraffin isomerization catalyst comprises the following steps of: dissolving 7.91 g of octadecyl trimethyl ammonium chloride into 224.0 mL of a NaOH water solution with the concentration of 3 mol/L, and then adding 11.0 g of bis(triethoxysilyl)ethane and 2.04 g of 3-thiopropyl triethoxy silane; stirring at room temperature for 20 hours, stirring at 95 DEG C for 24 hours, and filtering to obtain white sediments; washing the sediments at 70 DEG C for 12 hours by using 200 mL of an ethanol solution which contains 3.0 g of 36 percent by mass of hydrochloric acid to remove a surface active agent; treating at room temperature for 24 hours by using 65 percent by mass of HNO3 to obtain a product; and washing the product by using hot water to remove the HNO3, and drying to obtain the normal paraffin isomerization catalyst. The reaction is higher in activity and selectivity and stable in reactivity without environment pollution or equipment corrosion.