The invention belongs to the technical field of artificial board production. The technical proposal comprises the working procedures of wood chip screening and washing, stewing, hot grinding, glue blending and spreading, drying, paving and molding, heat pressing, and cooling. Mildew preventive is directly added in glue solution which is used during the glue blending and spreading, the weight of the mildew preventive is 0.1 to 0.2 percent of the glue solution; then ammonium sulphate which is used as a firming agent is added in, wherein, the weight of the ammonium sulphate is 3 to 4.5 percent of the glue solution, and the concentration is 20 to 30 percent; urea liquid which is used as buffer solution is added in, wherein, the weight of the urea liquid is 1.5 to 2 percent of the glue solution, and the concentration is 20 to 30 percent; the pH value of mixed liquid cement is adjusted to 7.0 to 8.0 by using sodium hydroxide solution the concentration of which is 20 percent, and the mixed liquid cement is used within 30 minutes; the modulated mixed liquid cement is added into fibre to be dried together before the fibre is dried; in the heat pressing stage, the heat pressing temperature is controlled between 170 to 190 DEG C, the heat pressing factors are 8 to 10s / mm, the plank stuff density is controlled between 850 to 870<3>. A medium and high density fibre panel which is manufactured in the invention is led to have mildewproof effect through adding with the mildew preventive, thus the service life of the plank stuff is prolonged, and the application range of the plank stuff is enlarged.