Live-cell superresolution imaging using organic fluorescent probes. Super-resolution imaging is a technique that can break the optical diffraction limit and achieve high-resolution imaging at the subcellular structural and molecular level. Organic fluorescent probe is a molecule or nanoparticle with fluorescent properties prepared from materials such as organic dyes or polymers, which has the advantages of high fluorescence quantum yield, low toxicity, and easy modification. Specific labeling and highly sensitive detection of various biomolecules and subcellular structures within living cells can be achieved by using organic fluorescent probes. Pythylenimine (PEI) -based cation carrier PV-1 and uses a variety of high-performance organic fluorescent probes into living cells, combined with a structured light illumination super-resolution microscopy imaging system to achieve super-resolution dynamic imaging of a variety of subcellular structures. Detection of tumor markers was achieved by using organic fluorescent probes. Tumor markers are a substance related to tumorigenesis, development and metastasis and can be used as important indicators for tumor diagnosis and treatment. Organic fluorescent probes can be used to design different response mechanisms according to different tumor markers, thus enabling high selectivity and high sensitivity for the detection of tumor markers. Based on the small molecule fluorescent probe, the detection of enzymatic tumor markers such as serine protease, β -galactosidase, β -glucosidase was realized, and validated in tumor cells and animal models.