Through anisotropic Ag overgrowth on the surface of Au nanobipyramids (AuNBPs), high-purity and sizecontrolled Ag nanorods (Au/AgNRs) are obtained by a simplified purification process. The diameters of the Au/AgNRs are determined by the size of the as-prepared AuNBPs, and the lengths of the Au/AgNRs are tunableusing 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/AgNRs have excellent sensing potential. The tunable optical properties and strong electromagnetic effect of the Au/AgNRs, along with their superior SERSsignal enhancement, show that Au/AgNRs are promising for further applications in plasmon sensing and biomolecular detection.of Nanjing Institute of Technology (CKJB201411, QKJB201409, YKJ201538); Qing Lan Project and Priority Academic Program Development of Jiangsu Higher Education Institutions.