Alzheimer's disease is one of the most serious neurodegenerative diseases in the world．The brain of Alzheimer's patient after death showed two main neuropathological changes,i.e. senile plaques and neurofibrillary tangles,while the typical clinical symptoms of Alzheimer's disease include memory loss,mood swings,cognitive decline,and difficulty in speaking,writing and walking．Early diagnosis is essential for the prevention or treatment of Alzheimer's disease by introducing proper intervention．Biomarkers associated with Alzheimer's disease such as proteins,genes,miRNAs,complement system,kinin system and metal ions are reviewed in this paper,and the current clinical diagnostic methods and kits for Alzheimer's disease are also summarized．There is an urgent need to develop simple,rapid,and less invasive diagnostic techniques due to the invasion and high cost of the current methods．Meanwhile,the novel emerging detection methods based on immunoassay,fluorescence,bio-imaging,electrochemistry,nanotechnology and miRNAs are also presented,which have pushed forward the way of early diagnostics of Alzheimer's disease.