The improvement of wheat strawcement compatibility and wheat strawcement board property by xylanase pretreating wheat straw were studied. Results show that wheat straw may hinder cement hydration, when cement mixed with wheat straw(untreated), the peak temperature T reduce from 42.5℃ to 23.5℃, the compatibility factor CA reduce to 30.49% and the bonding water content of cement is reduced. During the pretreatment process, xylanase dissolves part of xylan from wheat straw with the result that the oligosaccharides dissolution of wheat straw in the alkaline cement environment is reduced, furthermore, hinderance of cement hydration by wheat straw is also reduced. When xylanase pretreated wheat straw and cement are mixed, compared with untreated wheat straw, its peak temperature T improves to 28.5℃, its compatibility factor CA improves to 50.04%, its bonding water content of cement is also increased. The result of XRD analysis shows that after xylanase pretreatment the cement of its mixture has lower peak intensity of clinker and stronger peak intensity of hydration products(Ca(OH)2). The properties of wheat straw(xylanase pretreated)cement board are better than wheat straw(untreated)cement board.