A raw paper prepared by a mixed pulp including straw pulp, which can be used to prepare textbooks, writing papers and office paper with good performance, and the producing method of said raw paper are provided. The weight proportion of the straw pulp in the mixed stock is from 10% to 100%, and the straw pulp has a hardness of KMnO4 value 10-17, an average fiber length of 0.1-2.5 mm, a tensile index of 23-57 Nm/g, a tearing index of 3.0-6.0 mN·m2/g, a folding endurance index of 2-6 kPa·m2/g and a whiteness of 28-50%. Either, the L value of the hue of said raw paper is 65-95, a value is 0-5, and b value is 0-40. The KMnO4 value of hardness of the pulp after oxygen delignification is 10-14. The method includes: adding grass-series raw material into a digester, then adding cooking liquor, heating the cooking liquor to 100-200°, pressurizing to 0.3-0.9 MPa, cooking for 150-250 min, extruding the pulp, washing and obtaining the straw pulp. The amount of the ammonium sulfite of the cooking reagent is 5-20% of the absolute dry material, and the amount of the sodium hydroxide is 0-15% of the absolute dry material, the liquor ratio is 1:2-15.