Provided are a rapid detection method for a condition of landfill leachate polluting groundwater and an application thereof. The rapid detection method includes: carrying out fluorescence detection on groundwater in a specific region of a landfill, and determining whether the groundwater is polluted according to a ratio of fluorescence intensities at specific excitation/emission wavelengths in a specific fluorescence region. The rapid detection method provided by the solution establishes characteristic fluorescence spectrum regions, fluorescence intensities and regular characteristics thereof of organic matters in leachate-polluted groundwater of a landfill in a fluorescence spectrum region, and can achieve the rapid detection of a condition of landfill leachate polluting groundwater by means of a portable fluorescence detector on site. The detection method provided by the solution is characterized by rapid detection, no need of chemical reagents, simple operation, high detection sensitivity and lower cost.