The A-level fireproof floor substrate is made of high-density composite of solid wood fibers and inorganic materials, which maintains the texture of solid wood while achieving the A-level fireproof level. Its strengthening performance makes its wear resistance reach over 15000 revolutions per minute, several times higher than traditional flooring. Achieved waterproof level, fearless of boiling, soaking, water immersion, and dampness. The formaldehyde content of adhesive free composite reaches E0 level, which is more environmentally friendly than traditional flooring. This is a technological, safe, environmentally friendly, and durable substrate that is an ideal material for manufacturing wooden flooring.