Chronic non-specific low back pain (CNSLBP) is a prevalent condition among older adult and has been associated with an increased risk of executive function impairment. Studies have shown that older adults with chronic pain are more likely to show poor cognitive performance than healthy controls. Cognitive performance is particularly important when managing pain in older adults, especially for some executive functions (e.g., inhibition, switching, working memory) because pain and executive functions have their bidirectional relationship. Further, executive dysfunctions are associated with a decline in functional status among older adults, particularly the impairment of instrumental activities of daily living. Given the above, the preservation of executive functions emerges as a pivotal consideration among old adults with CNSLBP. Studies have provided preliminary evidence of the correlation between brain changes associated with chronic pain and cognitive functions. For example, multisite chronic pain may contribute to an increased risk of cognitive decline via structural change in hippocampal atrophy. For another example, functional brain changes in chronic pain reduced the deactivation of several key default mode network regions, thereby predisposing individuals to cognitive impairments. Despite the aforementioned brain changes, no research has provided direct evidence to support the hypothesis that structural and functional brain changes caused by CNSLBP in older adults may be associated with cognitive decline. Specifically, whether CNSLBP may lead to structural changes (e.g., smaller 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) associated with cognitive decline remains unclear. With the help of neuroimaging, the knowledge about the underlying brain mechanisms between CNSLBP (chronic non-specific low back pain) and executive functions can be explained. To gain a better 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. The results of this study have the potential to quantify the association between CNSLBP-related brain changes and executive functions in older adults, and provide insights into the development of new treatment strategies to improve or prevent executive function decline in older adults with CNSLBP.