This study focused on effects of thermomechanical treatment, acid hydrolysis and enzymatic hydrolysis of rice straw fibre on its water resistant. Xylose and arabinose yields were 19.97% and 2.55%, respectively with thermomechanical treatment, 24.35% and 3.18% with acid hydrolysis, and 20.11% and 2.73% with enzymatic hydrolysis. The acid treatment dissolved hemicellulose significantly, leading to more fines and more voids in the surface of the rice straw fibre. The fines showed a higher water retention value (WRV) of 137.41% and exhibited higher swelling capacity. An increase in acid loading resulted in the increased WRV. The enzymatic hydrolysis increased the crystallinity of cellulose, but no significant correlation could be found between the chemical component and the water resistance of the rice straw fibre. (c) 2010 Elsevier Ltd. All rights reserved.