Abstract: Early diagnosis and precise treatment of hepatocellular carcinoma (HCC) are key to improving the prognosis of this disease, with enhanced computed tomography (CT) being the preferential diagnostic imaging method. Flexible subtraction CT technology can contribute to a significant enhancement of the contrast and image quality of blood vessels and lesions and result in an improvement in the rate of detecting small HCCs. Moreover, it can be used to accurately assess the tumor activity of HCC after interventional surgery via dynamic iodine concentration analysis, without the need to alter the amount of the iodine contrast or radiation dose, thus contributing to significant improvements in the efficacy of early diagnosis and postoperative evaluation. In this paper, we summarize the principles and advantages of flexible subtraction CT technology and its application in the treatment of HCC.