In our work, the top 10 DEGs of DNA methylation associated with AD were selected: RPL5, RPLP0, RPS15A, RPS18, RPS23, RPS27A, RPS29, RPS3, RPS6, and RPSA. Through the analysis results of the ROC curve, RPS23, RPSA, and RPLP0 all had very excellent diagnostic accuracy. The gene discussed is RPL5; the disease is Alzheimer disease.