The invention discloses a detection method for the fingerprint of cassia seeds. The method for establishing the fingerprint comprises the following steps: 1, preparing a cassia seed sample solution; 2, preparing a reference substance solution; 3, respectively precisely sucking the sample solution and injecting the sample solution into a liquid chromatograph, and recording a chromatogram map; and 4, exporting the cassia seed fingerprint obtained in step 3, importing the cassia seed fingerprint into a traditional Chinese medicine chromatogram fingerprint similarity evaluation system, selecting chromatographic peaks existing in all the chromatogram maps of the cassia seeds in different batches as common peaks, carrying out mean value calculation to generate the reference fingerprint of the cassia seeds, and calculating the relative retention time and the relative peak area of every common peak. The cassia seed fingerprint can completely and objectively characterize the quality of the cassia seeds. The detection method for the fingerprint has the advantages of simplicity, stability, high precision and good reappearance.