Abstract： Objective To study the metastructure volumes of medial temporal lobe in diagnosis the patients with Alzheimer's disease (AD) using 3 dimensional MRI.Methods 23 AD patients according to DSM-Ⅳ criteria and 23 normal controls (NC) were examined with 3D-MRI.Hippocampus formation,amygdala,entorhinal cortex ( EC ),perirhinal cortex ( PC),and comu temporale were measured with 3D-MRI.Results Sensitivity and specificity of diagnosis AD were 73.9％,97％ ( Hippocampus formation) ;39.1％,95.7％ (amygdala) ;73.9％,95.7％ (EC) ;95.7％,87.0％ (PC) and 34.8％,39.1％ ( cornu temporale).Overall discriminate function =cornu temporal × 3.887 + PC × 5.960 - EC × 0.074 + amygdale × 3.489 + hippocampus formation × 6.656- 22.449.Over-all-accuracy was 91.3％.Conclusion The total volume of PC can better diagnosis the mild to moderate AD than other structure of medial temporal lobe.The changes of the medial temporal lobe volume could be used in diagnosis the patients with Alzheimer's disease.