Backgrounds Cognitive impairment is prevalent among older adults and results in degraded quality of life for older adults. As the population ages, this may cause a huge burden to society. Research has demonstrated that physical exercise is beneficial to cognitive function. The purpose of this meta-analysis was to critically assess the effect of Tai Chi exercise on global cognitive, executive, and memory functions in older adults. Methods After a thorough electronic search and selection, eight studies were included in this meta-analysis with two cross-sectional and six intervention studies. Nine variables included in this meta-analysis were: mini mental status examination (MMSE), Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog), trailmaking test part A (TMA), trailmaking test part B (TMB), digit span test forward (DSF), digit span test backward (DSB), visual span test backward (VSB), verbal fluency test (VFT), and word delay recall test (WDR). The effect sizes and forest plots of these nine variables were generated. Results Four (MMSE, DSB, VSB, and VFT) out of nine variables were significantly improved after Tai Chi exercise with the effect sizes ranged from 0.20 to 0.46 (small to medium). MMSE represented global cognitive function, and DSB, VSB, and VFT represented memory function. Conclusion Tai Chi as a mind-body exercise has the positive effects on global cognitive, and memory functions, and more consistent positive effects were found on memory function, especially verbal working memory