The longitudinal elastic modulus and length-breadth Poisson's ratio of a thick high frequency hot pressing poplar laminated veneer lumber was determined using four-point bending method. Flexibility method and strain gauge method was used to determine the longitudinal modulus of elasticity. The experimental results showed that the values of longitudinal elastic modulus in the two measurements are relatively close, but there are also some differences. The influencing factors on the differences were discussed. The test results of high frequency hot pressing poplar LVL longitudinal elastic modulus showed that the longitudinal elastic modulus is close to or above the poplar veneer, which can be reference for substitution of the material for raw wood in heavy product box or even structural materials.