The invention relates to a fluorescent probe for detecting nitric oxide in mitochondria and an application of the fluorescent probe. The fluorescent probe has a general molecular formula: BDP-NO or BDP-NO-T, wherein BDP-NO is as shown in the general structural formula (I). The fluorescent probe can be rapidly located in the mitochondria and can be used for detecting NO in the mitochondria in situ in real time; in addition, the probe also has relatively good chemical and optical stability, solubility and biocompatibility, relatively high in NO selectivity and free of interference from active oxygen, active nitrogen and other species. A laser confocal imaging experiment proves that the probe has relatively good cell permeability and has no obvious toxic or side effect for cells and living organisms.