Laminated Veneer Lumber (LVL) panels made from birch (Betula platyphylla Suk.) veneers were tested for physical and mechanical strength properties in this study. The static bending test were conducted on the LVL, and bending test and shear test were conducted on veneer and three-lamination LVL. The effects of the relative humidity on the modulus of elasticity (MOE) and bending strength (MOR) of birch LVL with vertical load and parallel load were investigated. There were four relative humidities including 40%, 50%, 60% and 70%. The results showed that the MOE and MOR of LVL would diminished with the increase of relative humidity, the bending strength of veneer sample decreased as the relative humidity increased, and there was noticeable effect of relative humidity on shear strength of PF resin.