The invention discloses a CT imaging method and system. The method comprises the steps that a double-energy CT system is utilized for performing CT scanning on an object, a first complete projection data set is obtained in a first scanning mode, and a second non-complete projection data set is obtained in the second scanning mode on the basis of the first projection data set, a first attenuation coefficient image of the object is reconstructed, transcendental structure information of the object is extracted from the first attenuation coefficient image, and the transcendental structure information indicates the strength of an edge the extracted transcendental structure information is utilized as a constraint condition, and a second attenuation coefficient image of the object is reconstructed from the second non-complete projection data set. According to the CT imaging method, the transcendental structure information of the imaged object is used as the constraint condition of the reconstruction process, the data volume required by reconstruction can be greatly reduced, the pathological limited angle can be avoided well, and the internal reconstruction problem can be well solved.
