In the present study, an elastic-plastic stress analysis is carried out on a high-density thermoplastic-based composite cantilever beam loaded by a single force at its free end. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. The composite material is assumed to be strain-hardening. The Tsai-Hill theory is used as a yield criterion. The residual stress component of a, are determined for 0, 30, 45, 60 and 90degrees orientation angles. It is found that the intensity of the residual stress is maximum at the tipper and lower surfaces of the beam. The horizontal displacement component of it is greater than the vertical displacement component of v.