Objective: To explore the cerebral hemodynamic characteristics of elderly patients with brain changes evaluated based on computed tomography perfusion (CTP), and analyze its correlation and influencing factors with cognitive function decline. Methods: A total of 104 patients with age-related brain changes as indicated by imaging findings who visited our hospital from February 2023 to January 2025 were selected as the study subjects. All patients underwent cranial CTP examination and Montreal Cognitive Assessment (MoCA) assessment. According to the MoCA score, the patients were divided into cognitive normal group (MoCA ≥ 26 points, 73cases) and cognitive decline group (MoCA<26 points, 31 cases). Compare two groups of general clinical data and CTP parameters [cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP)] to analyze independent risk factors for cognitive decline. Results: There were significant differences in age, education years, hypertension, diabetes, smoking history, high density lipoprotein cholesterol (HDL-C), Fazekas score between cognitive decline group and cognitive normal group (P<0.05); The CBF and CBV of the whole brain and each lobe (frontal, temporal, parietal) in the cognitive decline group were lower than those in the cognitive normal group, while the MTT and TTP of the whole brain and frontal lobe were higher than those in the cognitive normal group (P<0.05); The total score of the Montreal Cognitive Assessment Scale was significantly positively correlated with CBF and CBV in the whole brain, frontal lobe, temporal lobe, and parietal lobe, and significantly negatively correlated with MTT and TTP (P<0.05); Age, years of education, decreased whole brain CBF, and prolonged frontal lobe MTT were independent risk factors for cognitive decline (P<0.05). Conclusion: Elderly patients with cognitive decline and brain changes exhibit significant cerebral hypoperfusion. Age, years of education, and insufficient blood flow in the whole brain and frontal lobe are independent risk factors for cognitive decline.