Neuronal-derived exosomal Aβ42, T-tau, and P-T181-tau have been demonstrated to be biomarkers of Alzheimer's disease (AD). However, no study has assessed the association of Aβ42, T-tau, and P-T181-tau between exosomes and CSF. This was a multicenter study with two-stage design. The subjects included 28 AD patients, 25 aMCI patients, and 29 controls in the discovery stage; the results of which were confirmed in the validation stage (73 AD, 71 aMCI, and 72 controls). The exosomal concentrations of Aβ42, T-tau, and P-T181-tau in AD group were higher than those in aMCI and control groups (all P < .001). The level of each exosomal biomarker was highly correlated with that in CSF. This study verified the agreement between CSF and blood exosomal biomarkers and confirmed that exosomal Aβ42, T-tau, and P-T181-tau have the same capacity as those in CSF for the diagnosis of AD and aMCI.