The purpose of this study is analyse the differences in cognitive health, geriatric fitness, and brain activity between female elderly people with and without mild cognitive impairment (MCI) to contribute to the development of strategies for the prevention and management of MCI. The study included 56 female elderly residents of G city, and the participants were divided into an MCI group (32) and a non-MCI group (24). Cognitive health was assessed by an MMSE, and geriatric physical fitness was measured by various indicators such as strength, flexibility, and balance ability. Brain activity was measured by EEG(Electroencephalogram) to record concentration, stress, and left and right brain activity. Data were processed using independent samples t-tests and multiple regression analyses. The results showed that the MCI group was older, had more chronic diseases, and had a lower MMSE scores compared to the non-MCI group. In geriatric fitness measures, the non-MCI group had higher scores in handgrip strength and balance ability. In brain activity analyses, the MCI group had higher workloads and left brain activity than the non-MCI group, but there was no significant correlation with overall cognitive health. Regression analyses showed that, among the elderly physical fitness variables, vigour had a significant effect on cognitive health, suggesting that physical robustness may enhance cognitive reserve. The MCI group had lower cognitive health and physical fitness compared to the non-MCI group and showed some differences in brain activity. In particular, handgrip strength had a significant effect on cognitive health, suggesting that an exercise programme focused on strength training may be an effective intervention for the prevention and management of MCI.