A new shear test method was developed for the fiber reinforced polymer composite material, using uni-body specimen, not attached dummy tab on the end of specimen for clamping by fixture. The cure cycle with in-process monitoring method was employed to manufacture the thick laminated composite specimen without degradation. Also, to apply Iosipescu shear test method, the fixture of the modified Wyoming type was designed and manufactured. A 3-dimensional linear finite element analysis was performed to predict the experimental results, with considering contact between the specimen and the fixture. From the this works, it was found that the in-plane shear modulus and shear strength were about 20% and 120% higher than those of the interlaminar, respectively.