The modified soluble starch has been prepared by two-step method, and then used it treating with pickled goat skin and filling to wet-chromed goat skin. Research found that the optimal conditions of the first step modification are: 85℃, w (HCl) 25%, 60 min; The optimal conditions with Fenton oxidation are: c(H2O2)0.10 mol/L，c(Fe2+) 0.10 mol/L, 40℃ and 60 min. The modified soluble starch by two-step method has certain tanning property which can improve the shrinkage temperature of pickled goat skin as high as 19.7℃, and its carboxyl and carbonyl contents can reach 2.07% and 4.73%, respectively. The leather filled by modified soluble starch gets obvious thickening effect (thickening as high as 14.81%). Through the physical-mechanics tests, the leather samples also conform to the industry standard.