The paper aims to research glueless fiberboard based on the co-milling technology of soybean and wood chips to solve the problem of free formaldehyde release in fiberboard. A certain proportion of soybean and wood chips were used to co-mill and prepare glueless fiberboard. The effects of slab density, slab moisture content, pretreatment time, hot pressing time and hot pressing temperature on the physical and mechanical properties of the glueless fiberboard were analyzed. In the single factor test range, the physical and mechanical properties of the slab increased with the increase of the density and slab moisture content. The analysis of variance showed that the hot pressing temperature had the greatest influence on the physical and mechanical properties of the slab. Under the optimal conditions, the fiberboard had a modulus of rupture (MOR) of 10.12 MPa, an elastic modulus (MOE) of 1653.94 MPa, a water absorption thickness swelling (TS) ratio of 19.7% and an internal bonding (IB) strength of 0.476 MPa. When the density of the sheet is 0.8 g/cm3, the pretreatment time is 3 d, the hot pressing time is 30 min, and the hot pressing temperature is 180 ℃, the pressed glueless fiberboard has the best comprehensive performance.