A bending deformation of bamboo laminates beam is respectively calculated with Classical Plate Theory(CPT),First order Shear Deformation Theory(FSDT)and Finite Element Method(FEM).In order to test whether the results obtained by theory analysis and numerical computation are rational or not, the realistic deflection of beam under loading is measured. The results show that the transverse shear effect of bamboo laminates is extremely serious while the ratio of span thickness is comparatively small;the deflection obtained by FSDT and FEM under transverse shear effect is accurate enough;as transverse shear effect is approched to feeble,the solution of CPT is closer to practice than that of FSDT.