The invention discloses a continuous pressing device for composite materials, and particularly relates to a continuous pressing device for wood-plastic composite door production. The continuous pressing device for the composite materials comprises a support part, a steel belt and driving roller system and a pressure applying system. Pressure in the vertical direction provided by pressure oil cylinders is converted into direct continuous pressure of upper and lower steel belts through pressure transfer roller columns rolling in situ, and pressure of the steel belts is controlled through the relative distance between a roller barrel support and a stand column. The continuous pressing device is used for producing wood-plastic plates, is high in efficiency and low in energy consumption, and can reduce the cost of composite material products, reduce the labor intensity and achieve integral forming of a local structure.