In this study, a total of 60 AD patients with Aβ deposition will beenrolled.Qualified subjects will complete PET imaging scan of Tau imaging agent inXuanwuHospital, and each subject will receive three of the following five imaging agents: PI-2620, APN1607, AV1451, RO948 or GTP1.The imaging time interval between the two tracers should be at least 4 days but less than 4 weeks. All PET scans of each subject were completed within 3 months.To compare the different Tau tracers' binding ability (SUVR or Tau distribution change) of the same subject in AD population. Obtain the safety data of each tracer after injection.