Alzheimer's disease （AD） is a neurodegenerative disorder characterized by amyloid-β （Aβ） plaque deposition， neurofibrillary tangle （NFT） formation， and chronic neuroinflammation. Its global incidence and mortality continue to rise， yet effective curative therapies remain unavailable. In recent years， dysregulated cholesterol metabolism and immune-inflammatory responses have been increasingly recognized as key drivers of AD pathological progression. Both clinical and experimental studies have shown that patients with AD exhibit disrupted cholesterol homeostasis and aberrant T-cell function， with a significant correlation between these alterations， suggesting that cholesterol metabolic disturbances may participate in and amplify neuroinflammatory responses by modulating T-cell differentiation and activation states. This review systematically delineates the coupling relationship among cholesterol homeostasis imbalance， T-cell abnormalities， AD neuroinflammation， and related pathological injury. Specifically， we summarize the immunometabolic pathological links spanning the peripheral and central compartments， ranging from the effects of peripheral cholesterol metabolic disturbances on T-cell activation， differentiation， and blood-brain barrier permeability to the regulatory role of impaired brain cholesterol homeostasis in infiltrating T-cell inflammatory responses， glial activation， and neural microenvironment remodeling. We further highlight how abnormalities in cholesterol synthesis， transport， efflux， and oxidative product accumulation promote Th17/Treg imbalance， enhanced CD8⁺ T-cell effector activity， increased inflammatory cytokine release， as well as Aβ deposition， blood-brain barrier disruption， glial activation， and neuronal injury. In addition， we review recent progress in natural herbal formulas and bioactive phytochemicals that alleviate T-cell abnormalities and neuroinflammation through restoration of cholesterol homeostasis. Taken together， current evidence suggests that cholesterol homeostasis imbalance is not only a fundamental metabolic abnormality in AD， but may also construct and amplify AD neuroinflammation and related pathological injury by reshaping T-cell immunophenotypes. Therefore， immunometabolic intervention strategies aimed at restoring cholesterol homeostasis may provide a new theoretical basis for mechanistic studies and multi-target prevention and treatment of AD.