One of the main contributors to water pollution is heavy metal ions, which is dangerous for both human health and the environment even in tiny amounts. Heavy metal ions have been discovered to be biomarkers for several diseases and pathological situations in bodily fluids like sweat and serum. Therefore, in ecological environmental supervision and precision medicine, the quick and accurate detection of heavy metal ions plays a critical early warning role. This article firstly compares the widely used detection methods at present and then summarizes the heavy metal ion sensors developed based on MEMS technology, which can be divided into UV-visible spectrophotometry, colorimetry, fluorescence detection, luminescent chemistry, electrochemical method, and cantilever beam detection method according to the detection principle. Based on the aforementioned detection methods, the present portable instruments and systems developed are summarized, and the development trend and application prospect of heavy metal ion detection sensors and systems. Keywords:h