Current evidence supports that Alzheimer's disease (AD) was initiated when β-amyloid was abnormally processed. This was followed by formation ofβ-amyloid plaques which led to neuronal injury, synaptic dysfunction and neuronal loss. A recently developed hypothetical model of the temporal evolution of AD biomarkers proposes that five AD biomarkers depart markedly from normal in a sequential manner. Amyloid biomarkers may be found 10-15 years before the first clinical symptoms appears. Neuronal injury and degeneration biomarkers present later in the disease course but correlating better with concurrent clinical symptoms. We reviewed the development, advantage, and shortcoming of each biomarker and a brief overview of other novel imaging techniques in the research of AD.