Nonalcoholic fatty liver disease (NAFLD) is now recognized as the most common liver disease in the world. Nonalcoholic steatohepatitis (NASH), the most advanced form of NAFLD, can progress to cirrhosis and hepatocellular carcinoma. Computed tomography (CT) and magnetic resonance imaging (MRI) are being used as non-invasive diagnosis for the fatty liver in NAFLD patients. The present study utilized CT and MRI to examine liver fat mass in human liver chimeric mice (PXB mice, PhoenixBio, Co, Ltd.) fed a choline-deficient, L-amino-acid-defined, high-fat-diet (CDAHFD, A06071302, Research Diets, Inc.) for 28 and 85 days in order to produce a diet-induced NAFLD. Serum chemistry and liver histopathology were also conducted. CT and MRI revealed that the CDAHFD-fed PXB mice (model mice) had higher levels of fat content in the liver compared to the control diet-fed PXB mice from 14 to 56 day. In serum, the model mice had higher levels of total bilirubin compared to the control mice. Histopathological examinations revealed that Picro-Sirius Red-positive collagen fibers were observed at 28 and 85 days in the control mice and model mice. These results indicate that CDAHFD can induce fatty liver in PXB mice as seen in human NAFLD and that CT and MRI may be useful non-invasive methods for evaluation of liver fat in mice.