Abstract: The expressions for the stress field distributions in the matrix and the fiber were derived using the theory of elasticity and the shear lag theory. The effects of fiber volume fraction, fiber aspect ratio and matrix yield strength on the stress distributions and the stress transfer were investigated. It is shown that the stress distributions in the matrix and the fiber and the plastic behavior in the matrix are of significant non uniformity; there are significant stress transfer from the matrix to the fiber and the partition between the matrix and the fiber.