The current review summarizes the potential mechanism of AD, including genetic factors, amyloid-cascade hypothesis, neuroinflammation and immunity, vascular pathology and oxidative stress, propose some related biomarkers from both CSF and imaging, and discuss therapeutic strategies including symptomatic treatment, immunological therapy, target in and out Aβ and Tau treatment, and non-pharmaceutical treatment. This evidence concerns the gene MAPT and Alzheimer disease.