Abstract: A computation model for critical buckling load of composite thin tube was presented. Based on the plane hypothesis and small deformation assumption, a simplified method was presented for equivalent bending stiffness of composite beam. According to the geometrical symmetry and force symmetry of tube under axial compression, the local buckling of tube was transformed into the problem of the bending deformation of the axial and circumferential strips. On the basis of the stability theory of shell, the computation model for the stability of longitudinal strip on elastic foundation was established, and the analytical formula for the buckling bearing capacity of the composite tube was obtained. Compared with the engineering calculation formula, they are similar in form and the correction factor can be obtained directly from the model, rather than from experience. Axial compression test of three kinds of laminated composite tubes was conducted, and the experimental results are consistent with the theoretical prediction. Comparing the experimental data in literature with the theoretical calculation results, the deviation meets the requirements of engineering accuracy, which verifies the correctness of the model.