The invention relates to a production process of modified fiberboard, which includes: chipping, cooking and grinding, preparation of modified fiber material, drying, preparation of blank material, cold pressing, hot pressing, sawing, sanding and thickness determination, etc. step, wherein, in the preparation step of the modified fiber material, calcium powder is applied to the fiber material, and calcium powder is used to replace part of the wood fiber. When filling, the calcium powder is first mixed with glue, and then mixed with the fiber material , so that the gaps between fibers are filled with a mixture of calcium powder and glue, thereby improving the physical and chemical properties of the fiber board, achieving the purpose of increasing the density of the board, reducing wood consumption, improving the static bending strength and elastic modulus of the board, and The practical effect of reducing the production cost of fiberboard and effectively saving wood resources. Compared with ordinary fiberboard, it can save about 20% of wood, and the modified fiberboard produced has the advantages of high strength, strong nail holding force, good bending resistance, strong stability and flame retardancy.