Abstract: The amount of damaged starch, WSI and WAI et al were measured in order to investigate the effects of the particle sizes on the physicochemical properties of corn powder. The results showed that amylose content decreased slightly at beginning and maintained stable, while angle of repose, water retaining capacity, WSI, WAI and damaged starch content present an opposite trend. Meanwhile, the thermal stability and retrogradation degree of corn powder dropped, and the starch gelatinization degree went up during the same particle size range. Moreover, SDS-PAGE results indicated that grinding did not promote the degradation on protein in the corn powder.