Graphite oxide (GO) suspension was obtained by ultrasonically peeling, and it was compounded with starch / Polyvinyl alcohol (PVA) solution to prepare starch / PVA / GO nanocomposite. It was found that, GO could be evenly dispersed in the starch / PVA composite, and the compatibility of starch and PVA was significantly improved. GO could destroy the hydrogen bonding between PVA and starch molecules. Moreover, GO could form new hydrogen bonding with starch and PVA, but it had little effect on the crystal structure of starch and PVA. GO could limit the movement of starch and PVA chains. As a result, with the addition of 1wt% GO, the Tg of the nanocomposite reached up to 97.7 ℃. GO could improve the tensile strength of the composite significantly. With the addition of 1wt% GO, the tensile strength of the composite reached a maximum of 24.8 MPa, which was 71% higher than the material without GO. In addition, GO could effectively reduce the water absorption of composites. The water absorption reduced by 7% with the addition of 1wt% GO. The present work prepared nanocomposites with excellent properties, which showed promising potential for developing high performance of starch / PVA composites.