ObjectiveTo systematically review the effects of bilingual training on cognition for older adults. MethodsResearches about bilingual training for cognition for the older adults were retrieved from PubMed, Web of Science, ScienceDirect, SpringerLink, Wanfang Data, and CNKI from 2011 to May, 2021, supplemented by references backtracking and manual retrieval. The data was extracted for analysis. ResultsA total of 21 researches were included from twelve countries, which published mainly on journals of medicine, neurology, psychology, biology, etc., in 2017 and 2019. Most of the researches were prospective researches and retrospective researches, and the targeted groups including healthy people, people with dementia and people with Alzheimer's disease (AD). The objects mainly involved the effects of bilingualism on cognition, the pathways and the limitations. ConclusionBilingual training may improve the cognition for older adults, through the brain connection related with memory, attention and execution, to delay the onset of AD or dementia; which may associate with the improvement of brain structure and function, including connectivity among regions, activation of cortical circuits, and structural integrity and plasticity. The effects are mainly on execution and perception, and delaying the cognitive decline, which appear in a short term. Bilingual training may finally promote language function, maintain the integrity of the brain structures, and compensate cognitive decline using more potential neural circuits. However, these researches need more uniform criteria for subjects, more reasonable control conditions, and more uniform paradigms.