The present invention discloses a detecting method of the article detection device is formed from a single DR subsystem and an individual CT subsystem, the method comprising the steps of: obtaining first projection data via a beam attenuation coefficient by using the DR subsystem to the A projecting layer of an article at a first projection angle, and obtaining second projection data via a beam attenuation coefficient by using the CT subsystem to project the a-layer of the article at a second projection angle different from the first projection angle; and judging whether the A-layer of the detected article exists a dangerous article, on the first projection data and the second projection data to obtain an initial assessment based on the A-layer of the detected article. In the present invention, by combining the projection data of the DR subsystem and the projection data of the CT subsystem, the data information to be used to judge the detected article, greatly increased, and therefore, both the detection accuracy and the speed are improved.