Abstract: Alzheimer's disease is a neurodegenerative brain disorder that leads to progressive cognitive decline. Synaptic dysfunction is regarded as an early pathological feature,playing a crucial role in cognitive decline. Transcranial magnetic stimulation, as a non-invasive brain stimulation technique that modulates cortical neuronal activity, can be utilized to assess cortical plasticity in the human brain for detecting synaptic function. This approach serves the goals of identifying early-stage Alzheimer's disease patients, predicting cognitive decline, and evaluating the effectiveness of treatment strategies. This article provides a comprehensive review of the application of synaptic plasticity assessment based on transcranial magnetic stimulation in Alzheimer's disease spectrum.