The misfolding and aggregation of specific proteins within nervous system occur in most age-associated neurodegenerative diseases including Alzheimer's disease (AD). This kind of disorders have been classified as the protein misfolding disease or proteopathy which share key biophysical and biochemical characteristics with prion diseases. In AD, β-amyloid (Aβ) and tau protein, capital agents for the senile plaques and intracellular neurofibrillary tangles, are called 'prionoids' indicating that proteins exhibit prion-like properties. In this review, we describe the prion-like mechanisms in the progression that the Aβ and tau are induced to misfold and self-assemble by a process of templated conformational change and then the lesion caused by the pathogenic agents spread out through the cell-to-cell transportation, including release of intracellular seeds by the donor cell, cellular uptake by the recipient and intercellular transport. This hypothesis will suggest new therapeutic strategies for AD, especially valuable in the pre-symptomatic phase.