Abstract: Resistant starches from Castanea henryi before and after in vitro digestion were made and purified.Their probotic functions and structural changes were intensively studied. The results demonstrated that these resistant starches before and after digestion had good proliferative effect ( p < 0.05) on bifidobacterium and lactobacillus, and significant inhibitory impact ( p < 0.01) on Escherichia coli and Clostridium perfringens, and no obvious influence ( p > 0.05) on Enterococcus faecalis and Corynebacterium fusifome. The increasing total acidities of fermentation liquids demonstrated that these resistant starches before and after digestion could be used by intestinal probiotics.Compared with resistant starch, digested resistant starches increased specific surface areas, and had more greater specific surface areas after in vitro anaerobic fermentation.Average degree of polymerization of resistant starch decreased significantly ( p < 0.05) compared with native starch. After fermentation, average degree of polymerizations of resistant starches before and after digestion decreased. Crystal type of resistant starch was type V, then turn into type B after digestion.After fermentation, crystal types of resistant starches before and after digestion all became type A. Meanwhile the degrees of microcrystalline, submicrocrystal and total crystallinity obviously decreased ( p < 0.05) compared with before fermentation.