Nano rice starch prepared by ultrasonic-assisted inverse suspension polymerization was investigated on its physicochemical, gel structure and morphology properties. Water solubility index (WSI) under different temperatures and water absorption index (WAI) of nano rice starch and native starch were studied in this paper. WAI of native starch was 8.67%, and that of nano starch increased 38.45%, compared with native starch. WSI of native starch was respectively 0.024%, 0.057%, 0.111%, 0.211% under 30°C, 40°C, 50°C, 60°C, however, that of nano starch respectively increased to 1.32%, 1.430%, 1.527%, 1.513%. Gel strength of nano starch was 3.20g, and native starch increased to 62.87g. The structure of native rice starch granules was polyhedron with pronounced edges, however, granule size of nano starch became small, and nano starch appeared significant agglomeration.