Nanoscopic optical imaging has made prominent progress in recent years, which provides a powerful tool for modern biology science. Superresolution optical imaging allows for the observation of ultra-fine structures of cells, cellular dynamics and cellular functions at nanometer scale or even single molecular level, which greatly promotes the development of life science and many other fields. However, challenges still exist for super-resolution optical imaging for live cells and thick samples in terms of imaging depth, imaging speed as well as biomedical applications. This talk will review the recent progress in superresolution optical microscopy and present our recent work. By combining stimulation emission depletion (STED) microscopy and fluorescence lifetime imaging (FLIM), a STED-FLIM superresolution microscopy was developed to improve the spatial resolution of STED and also perform FLIM imaging at nanometer resolution. A new fluorescent probe with low STED laser power was designed for live cell mitochondria imaging. STED-FLIM imaging of microtubules labeled with ATTO647N inside HeLa cells and the mitosis process was obtained, which provides new insight into the cell structure and functions. In addition, coherent adaptive optical technique (COAT) has been implemented in a stimulated emission depletion microscope to circumvent the scattering and aberration effect for thick sample imaging. Finally, stochastic optical reconstruction microscopy (STORM) superresolution imaging of mitochondrial membrane in live HeLa cells was obtained by the implementation of new fluorescent probes, improved imaging system and optimized single molecule localization algorithm. This provided an important tool and strategy for studying dynamic events and complex functions in living cells.