In this report, we describe the applications and theoretical aspects of SERS phenomenon in nonaqueous systems, which mainly involves the structure of solid/nonaqueous system, the adsorption of some neutral and organic molecules, inorganic ions and other complex compound molecules, the process and mechanism of some electrochemical oxidation reduction reactions in organic solvents etc.. In this review, we also depict the similarities and differences in SER spectra of aqueous and non-aqueous systems.