The invention discloses a method for quantitatively detecting ustilaginoidea virens from seed-borne and soil-borne media. The method comprises the steps of (1) pre-treating a detected sample, and quickly extracting DNA of the detected sample; (2) constructing a standard curve; and (3) performing reaction by using a fluorescent nucleic acid thermostatic amplification detection technology. The method can be used for quantitatively detecting the ustilaginoidea virens, overcomes the defects of the conventional first generation LAMP (loop-mediated isothermal amplification) detection method, and has the advantages of high sensitivity, high specificity, low pollution, stable reaction and the like. By adopting the strategy of sensitively detecting the reaction product by adopting a closed-tube detection technique, the method disclosed by the invention is unlikely to be affected by pollutants and can be used for detecting a soil sample on site and analyzing and judging the reaction product, so that the method is extremely simple and suitable for being widely popularized and applied.