The invention discloses a method for performing infrared spectroscopic analysis on the SBS modifier content of modified asphalt, which comprises the following steps of: acquiring transmittance spectrum of an SBS modified asphalt sample with the known SBS modifier content by using a Fourier infrared spectrometer; computing a relative ratio A of a peak area which only belongs to a characteristic infrared absorption peak of the SBS to a peak area which only belongs to the characteristic infrared absorption peak of matrix asphalt on the transmittance spectrum; performing a parallel test for multiple times to determine the corresponding standard A value of the SBS modified asphalt sample; performing an infrared spectroscopic transmittance spectrum test on the SBS modified asphalt sample to be tested to obtain the transmittance spectrum of the sample; computing the relative ratio of the areas of the corresponding absorption peaks of the sample; and comparing the relative ratio with the standard A value to determine the SBS content of the sample. The general infrared transmittance spectrum test technique is adopted, so the method has the advantages of simple sampling process, convenient and quick establishment of a measuring method, correct and credible quantitative result, high sensitivity, high repeatability and suitability for wide application.