Recent resting fMRI studies have suggested that the functional connectivity of the brain's large-scale networks is associated with the cognitive decline of aging and is modulated by genetic factors. Our previous study found a significant association between interleukin-1 (IL-1 beta) C-511T polymorphism and working memory performance among elderly people. This study investigates the effects of IL-1 beta C-511T polymorphism on the functional connectivity of the cognitive division of the cingulate cortex [i.e., the anterior midcingulate (aMCC)] in non-demented Han elderly people and tests the hypothesis that T/T carriers are associated with lowered FC. Non-demented elderly males (n = 95) received resting MRI scanning, genotyping, and cognitive evaluation using the cognitive abilities screening instrument (CASI) and the Wechsler digit span task test. The functional connectivity map in each subject was derived based on positive correlations of low-frequency fMRI fluctuations with a seed in the aMCC according to structural definition. Between-group difference was compared by random effect analysis. Compared to the C/C or C/T carriers, the T/T carriers had a significantly worse CASI performance, especially in the abstraction scores. For the functional connectivity analysis, the T/T carriers exhibited significantly lower functional connectivity with several prefrontal areas and the left putamen. The cortico-striatal connection between the aMCC and left putamen was correlated with the CASI abstraction and attention scores. The results were consistent with our hypothesis and supported that the brains' functional connectivity in elderly people may be modulated by genetic polymorphism associated with local inflammation processes.