Concerns over exposure to mercury have motivated the exploration of cost-effective, rapid, and reliable method for monitoring Hg 2+ in the environment. Recently, surface-enhanced Raman scattering (SERS) has become a promising alternative method for Hg 2+ analysis. SERS is a spectroscopic technique which combines modern laser spectroscopy with the optical properties of nano-sized noble metal structures, resulting in substantially increased Raman signals. When Hg 2+ is in a close contact with metallic nanostructures, the SERS effect provides unique structural information together with ultrasensitive detection limits.This review introduces the principles and contemporary approaches of SERS-based Hg 2+ detection. In addition, the perspective and challenges are briefly discussed.