A total of 26 NC subjects were selected and their peripheral venous blood was collected to find a more stable biomarker for the early diagnosis of AD by detecting the levels of serum SIRT1, IL-6, T-tau, P-tau-181, and Aβ1-42 proteins in the three groups of subjects, to provide ponderable help for the early diagnosis of AD. This evidence concerns the gene MAPT and Alzheimer disease.