Objective To investigate the effect of intermittent low flow oxygen inhalation on cognitive function in patients with vascular dementia. Methods 116 cases of vascular dementia were divided into treatment group (n=58) and control group (n=58). Both groups received the routine drugs, and the treatment group received intermittent low flow oxygen inhalation in addition. They were assessed with the Mini Mental Statement Examination (MMSE) and Activity of Daily Living Scale (ADL) before and 8, 16 weeks after treatment. Results There was not significant difference between groups in scores of MMSE and ADL 8 weeks after treatment, but was 16 weeks after treatment (P<0.01). Conclusion Intermittent low flow oxygen inhalation can improve the cognitive function and quality of life in patients with vascular dementia.