Lysosome fluorescent imaging has been widely used in the field of biological staining and diagnostics, which plays a key role in understanding intracellular metabolism and various physiological processes. However, for most currently used small-molecule lysotrackers, the photostability is often unsatisfactory when used for long-term and real-time visualization of lysosomal dynamics. Herein, we reported a new lysosome-targetable photostable fluorescent probe (i.e. MPL-NPA), and results showed that MPL-NAP possesses superior photostability, appreciable tolerance to pH change, low cytotoxicity and high lysosome targeting ability. These findings confirm that MPL-NAP is a well-suited imaging agent for targeting lysosome and enables long-term and real-time monitor of lysosome morphological changes under physiological processes. [ABSTRACT FROM AUTHOR]