Shear modulus of thin wood composite materials is one of several important indicators characterizing mechanical properties. However, there is not an easy method to obtain this value. This paper explores the use of a newly developed cantileverbeam free vibration test apparatus to detect the shear modulus of thin wood composite materials by measuring the first order free vibration cantilever specimens and its logarithmic decrement of vibration to calculate shear modulus. Six sets of commercially purchased thin wood composite materials having three different fiber types were tested. The results indicate that there is a significant linear correlation between shear modulus and bending modulus of elasticity obtained from cantileverbeam free vibration method.