Varietal purity is the most important quality parameter of maize seeds, which has direct and prominent influence on the output and quality of maize. For the first time, to our knowledge, we present a new kind of terahertz (THz) scanning imaging technology for identification of maize seeds. Terahertz images of DNA samples are obtained by point-by-point scanning imaging technology. Inspection and identification of specific kinds of seeds are realized successfully by using the method of component pattern analysis. In this method, what we need are only data of image and absorption spectral information of samples; no specific features of samples are required. This technology provides a new approach for the detection and identification in biology and it can also be extended to poison inspection.