Abstract: Characterization of B_w/Ti composite fiber stress-strain response was explored.Both of experimental and composite consists of elastic deformation of fiber and elastic-plastic deformation of matrix. In addition,under the condition of firmly coherent interface between fiber and matrix as well as less than 50% volume fraction of matrix compc-nent,the composite fiber performs a high strength,high modulus and low plasticity behavior which means ensurement of excellant properties for fiber and limitation of plastic potentiality for matrix. Finally,comparison between experimental and theoretical results was made and the agreement of both was satisfactory.