The invention discloses a method for recognizing substances of a to-be-tested article with a multi-energy-spectrum X-ray imaging system. The method comprises the steps as follows: a transparency related vector consisting of transparency values of the to-be-tested article in N energy regions is acquired, wherein N is larger than 2; the distance between the transparency related vector and a transparency related vector consisting of N transparency mean values of multiple articles stored in the system in the N energy regions under multiple thickness conditions is calculated; the to-be-tested article is recognized as the article corresponding to the minimum distance. On the basis of the multi-energy-spectrum X-ray imaging system, the substance recognition method is provided through analysis ofthe multi-energy-spectrum substance recognition problem. Compared with a traditional dual-energy X-ray system, the system has significantly improved substance recognition capacity in the multi-energy-spectrum imaging theory, and the improvement of the substance recognition capacity has great significance in checking drugs, explosives and other prohibited goods particularly in the security check application field.