Plaque pH detection technology can detect the risk of caries and assist in the prevention of caries, with a mature theory and a relatively simple operation. With the increasing demand for clinical caries risk detection technology and the rapid development of microelectrode techniques, there is an increasing variety of types of microelectrodes that can detect the pH of dental plaque, including glass microelectrodes, metal oxide microelectrodes and ion-sensitive field effect transistors. The glass microelectrode was the first microelectrode to be applied in this field, but its structure is weak. Among the various options, the iridium oxide microelectrode has become the most promising caries risk detection electrode in recent years because of its high strength and excellent response. Metal oxide microelectrodes can also effectively compensate for the insufficient strength of glass microelectrodes. With advances in electrode technology, miniaturized, sensitive ion-sensitive field effect transistors have attracted the attention of researchers. Scientists have also recently developed a way to detect the pH of dental plaque with an optical no-contact technique. Optical contactless detection technology will not damage the dental plaque structure, so it has great research and clinical prospects. Future research will further improve the strength and performance of these electrodes on the premise of ensuring miniaturization and achieving noncontact detection.