Oriented strand boards (OSB) were made from flakes of fast growing tree specieses, such as Japanese fir and Wood oil tree, which testing for physical and mechanical properties were summarized as follows: Modulus of rupture (MOR) and modulus of elasticity (MOE) of OSB were higher than the particleboard which particles random aligned, and but there was no significant difference in internal bonding strength (IB), screw-holding strength (SH) and the dimensional stability between both types particleboard. The MaR, MOE, IB , SH and thickness swelling of two tree specieses particleboards increased with board density , but the water absorption showed reverse.