The in vitro tau aggregation assay can simulate the process of tau protein misfolding and aggregation in vivo, providing an important tool for studying the role of tau protein in disease. Tau protein is a microtubule-associated protein whose primary function is to stabilize microtubule structure in neurons, thereby supporting axonal growth and synaptic plasticity. However, under pathological conditions, tau protein misfolds and aggregates to form neurofibrillary tangles (NFTs), one of the core pathological features of Alzheimer’s disease. (AD) Abnormal aggregation of tau protein is not only closely associated with neurodegenerative diseases, but can also induce aggregation of other tau protein molecules through the “seed” effect.