The detection of ion concentration is of great significance in the fields of human health and environmental science. Compared with other ion detection methods, surface plasmon resonance (SPR) technology has the advantages of label-free detection, high sensitivity, and low detection limits, which brings new possibilities to the field of heavy metal ion monitoring. This article reviews the application and technical advances of SPR sensing technology in heavy metal ion detection. Firstly, this paper introduces the technical principles of SPR sensing. Then the paper focuses on the selection of sensing materials and surface modification, it emphasizes improvements in indicators such as sensitivity, linear dynamic range, specially for harmful heavy metal ions such as Pb²⁺ and Hg²⁺. Finally, the significant progress in terms of detection speed, sensitivity, etc. is introduced, and the development prospects of SPR technology is discussed.