Autoclave processing was applied to prepare wheat resistant starch RS3. The physicochemical and structure properties of product were studied. Results showed that the product contained 13.89% resistant starch. The water-holding capacity, solubility and swelling capacity increased along with increasing the temperature of water bath. The maximum absorption wave of the starch-iodin compound was at 594 nm, and a widen absorption peak in the curve was found between 580~610 nm. Most of the starch granules were rotundity, with strong polarization cross. Moreover the crossing points were in the centre of the granules. The product was hard to gelatinize but easy to retrogress, and the gelatinization temperatures was 68.7 ℃. Crystal type of this starch granule was C-type. The main characteristic peaks of the product in the infra-red spectrum figure are similar to that of the wheat starch.
