Hypochloric acid（HClO）is associated with various pathological and physiological processes such as neurodegenerative diseases，inflammation，and cancer due to its high oxidation and reactivity. Detecting HClO at the cellular level is of great significance for understanding the pathogenesis of various diseases. Therefore，scientists have designed and synthesized multiple series of small molecule fluorescent probes for intracellular HClO imaging. This article reviews representative cases of two-photon fluorescence probes based on recognition mechanisms，with the aim of providing design strategies for relevant workers.