This study was designed to detect the brain glucose metabolism in rat models of Alzheimer's disease (AD) by the application of (18)F-2-fluoro-deoxy-d-glucose positron emission tomography ((18)F-FDG-PET) and to provide new insights for the early detection of AD. Forty Wistar rats were randomly divided into 2 groups. Fifteen sham-operated rats were used as a control group. The remaining rats as a premodel group were intracerebroventricularly injected with ibotenic acid and were intraperitoneally injected with d-galactose, of which 15 rats were included as the experimental group. The above-mentioned 2 groups were assigned to Y-maze test and underwent (18)F-FDG-PET scanning. Positron emission tomography images were processed with SPM 2.0. The learning and memory skills were weakened in AD rats. Besides, the glucose metabolic activity of AD rats decreased in hippolampus, hypothalamus, insular cortex, piriform cortex, striatum, cingulate gyrus, stria terminalis, and parietal lobe and increased in olfactory bulb, cerebellum, midbrain, pontine, and retrosplenial cortex compared with the control group. Dorsal thalamus had shown both enhanced and reduced glucose metabolic activity. Our data indicate that the changed glucose metabolism in cerebral regions in (18)F-FDG-PET imaging could be an important predictor for early AD. © The Author(s) 2015.