Abstract: A method of measuring the interface bonding strength of C/Al camposite precursor wires and the effect on the Tensile strength had been studied in this paper.We also provided a small scale shear testing machine made by ourselve to measure the langitudinal shear strength of cumposite wires.The interface bonding strength was expressed by converting the longitudinal shear strength of camposite wire through calculation.Generally, interface shear strength is equal to the longitudinal shear strength multiplied by a coefficient.It is found in the experiment that for a certain interface shear strength range the tensile strength of composite wire is inverse proportional to the interface shear strength.