Abstract: Provided are a fault diagnosis apparatus and method based on fluorescence multivariate correction analysis of transformer oil, relating to the field of transformer fault diagnosis technology. Thus, the problem of large volume and weight of the apparatus, high costs, and inconvenience to use caused when in the related art, a fluorescence spectrometer is directly used to acquire the fluorescence spectrum of transformer oil is solved. The monochromatic excitation light of an optimal excitation wavelength generated by a fluorescence excitation source is used to excite the transformer oil in a fluorescence excitation detection apparatus to generate fluorescence. The fluorescence excitation detection apparatus generates the fluorescence according to the input monochromatic excitation light and inputs the fluorescence to a fluorescence signal acquisition and analysis apparatus.