Through anisotropic Ag overgrowth on the surface of Au nanobipyramids(Au NBPs), high-purity and sizecontrolled Ag nanorods(Au/Ag NRs) are obtained by a simplified purification process. The diameters of the Au/Ag NRs are determined by the size of the as-prepared Au NBPs, and the lengths of the Au/Ag NRs are tunable using different amounts of Ag precursor in the growth solution. Surface-enhanced Raman scattering(SERS) studies using Rhodamine-6G(R6G) as a test molecule indicate that the Au/Ag NRs have excellent sensing potential. The tunable optical properties and strong electromagnetic effect of the Au/Ag NRs, along with their superior SERS signal enhancement, show that Au/Ag NRs are promising for further applications in plasmon sensing and biomolecular detection. Through diameters of the Au / Ag NRs are determined by the size of of Au nanobods (Au / Ag NRs) The as-prepared Au NBPs, and the lengths of the Au / Ag NRs are tunable using different amounts of Ag precursor in the growth solution. Surface-enhanced Raman scattering (SERS) studies using Rhodamine-6G That the Au / Ag NRs have excellent sensing potential. The tunable optical properties and strong electromagnetic effect of the Au / Ag NRs, along with their superior SERS signal enhancement, show that Au / Ag NRs are promising for plasmon sensing and biomolecules detection.