The invention discloses a method for producing a straw fiberboard by using waste pulp residue obtained by producing unbleached pulp through crops straws and belongs to the field of production of fiberboards. The method comprises the following working procedures of washing the waste pulp residue obtained by producing pulp, drying in the air and sun, crushing, adding an adhesive, mixing and stirring, extruding and dehydrating by a die, and forming to obtain a finished product. According to the method, pulp residue wastes obtained by boiling and screening straw pulp for making paper are utilized, so that the environmental pollution problem caused by incinerating and stacking of the waste pulp residue is solved, and wastes are changed into the valuables. The method has the advantages of low cost, simple technique, high efficiency and good economic benefits; and in addition, a produced board is high in density, light in weight and low in cost, and can be applied to various fields of home decoration, warehousing and the like.