OBJECTIVE: This study aimed to analyze the effect and potential mechanism of cognitive intervention and rehabilitation training in elderly patients with diabetes mellitus complicated with mild cognitive impairment. METHODS: In this study, 128 elderly patients with diabetes mellitus complicated with mild cognitive impairment were randomly divided into the control group and the training group. The effects of the two groups were compared before and after the cognitive intervention. The expression of miR-134-5p was assessed by qRT-PCR. The relationships between miR-134-5p and Mini-Mental State Examination Scale and Montreal Cognitive Assessment Scale were evaluated. RESULTS: After 3-month management, the Mini-Mental State Examination Scale, Montreal Cognitive Assessment Scale, the Chinese version of the diabetes self-efficacy rating scale, and WHO quality of life brief were improved in both control group and training group, and the training group showed better improvement. Cognitive intervention and rehabilitation training restricted the expression of miR-134-5p. The levels of miR-134-5p were pertinent to cognitive function. CONCLUSION: Cognitive intervention and rehabilitation training might prevent the development of diabetes mellitus complicated with mild cognitive impairment by inhibiting miR-134-5p.