Abstract: In this work, wheat-straw (WS) was surface-treated with maleic anhydride (MA) and then melt blended with corn starch to prepare the MA-treated WS-reinforced thermoplastic starch composites. The effects of MA content on the mechanical properties, thermal stability, morphology and water resistance of the composites were investigated. The results indicated that the mechanical properties of the composites were improved at the WS content of 1 wt.% and the MA content of 4 wt.%. The composite also achieved the tensile strength of 2.76 MPa and the elongation at break of 158.24%. As for the thermal stability, the incorporation of MA-treated WS improved the maximum decomposition rate of the composites. Moreover, the composites showed a water contact angle of 83.6° at the MA content of 6 wt.%. The optimal content MA was determined as 4 wt.% for the composites on the basis of the investigation results.