An optical nanoprobe is a nanoscale probe that detects chemical or biological samples through optical signals. Its main components are usually inorganic nanoparticles, organic supramolecular assemblies, and organic-inorganic composites, etc. Currently, optical nanoprobes have been widely used in environmental monitoring, biomedicine, food safety, and other fields. This section mainly summarizes the luminescence mechanisms and biomedical detection applications of several common optical probe materials, including fluorescence, phosphorescence, upconversion luminescence, luminescence resonance energy transfer, and chemiluminescence, etc.