The present invention discloses a detecting method of an article detection apparatus composed of an individual DR subsystem and an individual CT subsystem, the method comprising: obtaining a first projection data on ray attenuation coefficient by using the DR subsystem to project an A-layer of an article at a first projection angle, and obtaining a second projection data on ray attenuation coefficient by using the CT subsystem to project an A-layer of the article at a second projection angle different from the first projection angle; and judging whether an A-layer of the detected article contains a dangerous article based on the first projection data and the second projection data so as to obtain a first judgment on an 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 amount of data information used to judge the detected article is greatly increased, therefore, both the detection accuracy and speed are improved.