The intracellular viscosity plays a pivotal role as a physicochemical factor and an important indicator of organelles performance. Abnormal changes in subcellular viscosity are often associated with cellular malfunction and various diseases. Nonalcoholic steatohepatitis (NASH) is the most common liver disease related with type 2 diabetes mellitus (T2DM), and both are linked to aberrant mitochondrial viscosity. In this study, we styled and screened a novel near-infrared probe termed MT-E, carrying the double bonds as the viscosity response groups, that was employed to image the viscosity changes in HepG2 cells, zebrafish and animal models. MT-E has a superior mitochondrial targeting ability, as well as a large Stokes shift (167 nm). Additionally, utilizing the excellent performance of MT-E, we first monitored the increased viscosity trends in both T2DM mice and NASH mice, suggesting that there is a strong correlation between T2DM and NASH. More groundbreakingly, we have successfully revealed, from fluorescence imaging, the extraordinary potential of Aloin in treating T2DM mice that can effectively reduce viscosity. This is a sign that MT-E may have a steering role in mitochondrial viscosity-associated disorders.