Abstarct: Thin-walled beams are widely used in engineering structures. The common feature of these structures, which are used in a wide range of industries such as civil engineering, mechanical engineering and aerospace, is the requirement of minimum weight. Reducing the weight of the beam leads to the importance of its vibration and dynamic properties. Whenever the amplitude values of the beam vibrations are large, the effect of geometric nonlinear components must be considered in the analyses and some phenomena that do not exist in linear analyses appear. The present research studies the vibrations and torsional-axial dynamic of a composite thin-walled beam. By considering the effect of section warping, large torsional deformations, the presence of axial force and initial torsion in the beam, the equation governing the motion is obtained using Hamilton's principle. The effect of fiber angle, initial torsion angle and axial force on the natural frequencies of the system is studied.