A novel material for biopulp-making, steam-exploded wheat straw (SEWS), was studied. During the steam explosion process, the hemicellulose was partly degraded and became water-soluble sugar as the carbon resource of the chosen microbe growth, and compared with non-SEWS, the degradation amount of cellulose decreased and the degradation amount of lignin increased for the fermented steam-exploded wheat straw (FSEWS) cultured with Phaneroehaete chrysosporiurn ME-446. Under the optimum conditions of solid-state fermentation (SSF), the degradation amount of lignin reached 60% on the 5th day and the fermented straw residue could be used directly as the material for pulp making.