Steam explosion, one potential commercial pretreatment method for lignocellulosic wastes, was used to improve methane production of bulrush. Steam exploded bulrush showed a higher methane yield than the raw sample. The effects of steam pressure, moisture content and residence time on the concentration of neutral detergent fiber (NDF) and methane yield were described using a second order polynomial equation. A minimum NDF content of 30.6% was achieved under pretreatment condition with moisture content of 16.55%, steam pressure of 1.52 MPa and residence time of 5.17 min. A maximum methane yield of 205.3 ml per degradable volatile solid was obtained at 11.0% moisture, 1.72 MPa steam pressure, and 8.14 min residence time. The breakage and disruption of rigid lignin structure by steam explosion was confirmed by thermogravimetric analysis. (C) 2010 Elsevier Ltd. All rights reserved.