The invention discloses an X-ray source array based real-time online industrial CT (computed tomography)detecting system. The system comprises a conveyor belt for conveying a to-be-detected object, wherein an X-ray source array of a carbon nanotube cathode and a detector array matched with the X-ray source array of the carbon nanotube cathode to conduct CT detection on the to-be-detected object are arranged on the outer side of the conveyor belt, and the system further comprises a control device for rapidly switching an X-ray source and reading a detector synchronously, and an image processing device used for acquiring a CT image detected by the detector array and storing and processing the CT image. The system greatly increases the scanning speed, rapidly finishes product detection, improves the production efficiency of a factory, and reduces economic cost.