The present disclosure relates to the technical field of CT detection, and in particular to a CT inspection system and a CT imaging method. The CT inspection system provided by the present disclosure comprises a radioactive source device, a detection device, a rotation monitoring device and an imaging device, wherein the detection device obtains detection data at a frequency that is N times a beam emitting frequency of the radioactive source device; the rotation monitoring device detects a rotation angle of the detection device and transmits a signal to the imaging device each time the detection device rotates by a preset angle; the imaging device determines a rotational position of the detection device each time the radioactive source device emits a beam according to the signal transmitted by the rotation monitoring device and the detection data of the detection device, and generates a CT image based on the detection data and the rotational position of the detection device each time the radioactive source device emits a beam. The present disclosure can accurately determine the rotational position of the detection device each time the radioactive source device emits a beam, so that it is possible to effectively reduce the image deformation and improve the accuracy of detection results.