A computed tomography method and system. The method comprises: acquiring original data (1110)； pre-processing the original data to obtain a pre-processing result (1120)； according to the pre-processing result, obtaining an artifact intensity (1130)； and according to the artifact intensity, updating a bad channel or air calibration table (1140). Updating the air calibration table comprises: acquiring a first air calibration table corresponding to a first temperature of a detector (810)； acquiring the real-time temperature of the detector (820)； and obtaining a second air calibration table corresponding to the real-time temperature according to the real-time temperature and the first air calibration temperature (830).
