The invention relates to a method for quickly identifying refuse landfill percolate in the sewage water discharged into a sewage treatment plant, in particular to a method for quickly judging whether percolate is illegally discharged into the sewage treatment plant. The method comprises the following steps: taking residual active sludge in the sewage treatment plant, then carrying out centrifugation on the residual active sludge so as to obtain a supernatant liquid; carrying out filtration on the supernatant liquid by a filter membrane (0.45 mu m) so as to remove suspended matters in the supernatant liquid to obtain a sample; taking a point every 2nm and then carrying out three-dimensional fluorescence spectrum survey on the sample so as to obtain a numerical three-dimensional fluorogram under the conditions that the excitation wavelength is 200 to 500nm, the emission wavelength is 250 to 600nm, the slit width is 5nm, and the scanning speed is 1200nm/min, wherein in case the fluorescence peak of the sample only refers to fulvic acid-lile substances (Ex/Em: 240/440nm) and humic acid-like substances (Ex/Em: 330/420 nm), but without protein-like substances, the numerical three-dimensional fluorogram shows that the refuse landfill percolate exists in the sewage water discharged into the sewage treatment plant, otherwise, the numerical three-dimensional fluorogram shows that no refuse landfill percolate exists in the sewage water discharged into the sewage treatment plant. The method of the invention has the advantages of simpleness, speediness, less required samples, high sensitivity, low cost, and capability of being widely applicable for quickly judging whether percolate is discharged into a sewage treatment plant.