Chronic non-specific low back pain (CNSLBP) is a common condition among older adults and has been associated with an increased risk of executive function impairment. Research shows that older adults experiencing chronic pain are more likely to show worse cognitive performance compared to healthy individuals. While there is a bidirectional relationship between pain and executive functions, cognitive performance especially for some executive functions (e.g. inhibition, switching, working memory) is crucial for managing pain in older adults. Furthermore, executive dysfunctions are associated with decline in functional status among the population, particularly in performing instrumental activities in daily living. Therefore, maintaining executive function emerges as a pivotal consideration for older adults with CNSLBP. Studies provide preliminary evidence that connects brain changes with chronic pain and cognitive functions. For instance, multisite chronic pain may increase the risk of cognitive decline through structural changes like hippocampal atrophy. Besides, functional brain changes in chronic pain may reduce deactivation several key default mode network regions, predisposing individuals to cognitive impairments. Despite the aforementioned brain changes, no direct evidence supports the hypothesis that structural and functional brain changes caused by CNSLBP in older adults may be associated with cognitive decline. It remains unclear that whether structural changes (e.g. reduced hippocampal, cerebellar gray matter, white matter volume in the right frontal region) and/or functional changes (e.g. deactivation of default mode network regions, heightened activation in the anterior cingulate cortex) cause by CNSLBP are associated with cognitive decline. With neuroimaging techniques, brain mechanisms connecting CNSLBP and executive function deficits can be explained. To deepen understanding of the brain mechanisms underlying executive function decline in older adults with CNSLBP, this study will directly compare pain intensity, executive functions, brain structure, and functional changes of the brain between older adults with CNSLBP and age-matched healthy controls. A longitudinal approach is established to quantify the relationship between CNSLBP-related brain changes and executive functions in older adults, providing insights into the development of new treatment strategies to improve or prevent executive function decline in older adults with CNSLBP.