Some metal oxides possessing surface-enhanced Raman scattering (SERS) ability have drawn tremendous attention recently for their good signal uniformity, chemical stability and biocompatibility. However, most of them present deficient Raman enhancement factors which cannot meet the rigorous requirement in SERS applications. It is desirable to develop efficient approaches to promote the SERS performance. The different inherent features of metal oxides compared with noble metals, endow the former abundant possibilities to tailor SERS performance, such as tailoring of bandgap, stoichiometry or excitons. The effective tailoring of several inherent properties of metal oxides simultaneously may contribute synergistically to the overall SERS performance. Therefore, we choose indium tin oxide (ITO) as an example to explore the possibility to integrate its inherent SERS-activity with its optical interference cavity, to further promote the SERS performance. This work demonstrates a synergistical approach to engineer the SERS-active metal oxide substrate, providing a general concept to manage the intrinsic SERS ability of metal oxide together with optical interference effect.