Methods of preparation of press-mass material by cavitation effect on plant material (pine wood, wheat straw) are considered. Mass containing easily and hard hydrolyzable polysaccharides of 13–18 and 28–37%, respectively is formed as a result of cavitation on pine wood with and without addition of sulfuric acid. Physical and mechanical properties of plate materials of cavitated press mass of pine wood obtained at different temperatures and compaction of pressure with varied humidity of wood carpet have been studied. The conditions of pressing to obtain plate materials of chipboard and wood fiber types for woodworking, furniture and construction industry without the use of synthetic binders have been selected. Cavitation processing of vegetable raw materials with and without hydrolyzing agent provides better fluidity of press-mass which allows to produce plate materials with good strength and hydrophobic properties under milder conditions: at pressure not exceeding 11 MPa and pressing temperature not higher than 160° C. High content of reducing substances in the resulting pressmassl contributes to strength and service properties of the obtained composite materials which are characterized by high environmental specifications.