To explore the effect of virtual reality (VR) technology cognitive rehabilitation training on improving cognitive function, daily life ability, and quality of sleep in patients with mild cognitive impairment (MCI). Methods: Sixty MCI patients were randomly divided into routine and VR groups of 30 each. The routine group used conventional cognitive training methods, and the VR group used cognitive rehabilitation training based on VR technology. Rehabilitation lasted 6 weeks for all patients. Before and 6 weeks after rehabilitation training, the Montreal Cognitive Assessment Scale (MoCA), Mini-Mental State Examination (MMSE), activity of daily living scale (ADL), Pittsburgh sleep quality index (PSQI), and semi-structured interviews were used to evaluate the clinical efficacy of the trainings. Results: After rehabilitation, the MoCA, MMSE, and ADL scores of both groups improved compared to the same group before training, and the VR group showed a greater improvement (P<0.05). The PSQI scores did not show a significant difference before and after training in either group (P> 0.05), and there was no significant difference between the groups (P>0.05). The semi-structured interview revealed that all patients in the VR group believed that cognitive rehabilitation training under VR improved cognitive function and were willing to continue VR cognitive rehabilitation function training. The routine group expressed satisfaction with the training outcome, while some patients reported no significant change in cognitive function after training. Conclusion: Cognitive rehabilitation training under VR technology can better improve cognitive function compared to routine rehabilitation training methods.