Objective To explore the effect of walking exercise intervention on chemotherapy-related cognitive impairment and sleep quality in patients with breast cancer. Methods Breast cancer patients who received chemotherapy for the first time in two departments were divided into two groups with 28 cases in each group by cluster random method.The control group received routine care of chemotherapy.The experimental group received walking exercise intervention based on routine care of chemotherapy.Outcomes were evaluated by using the Functional Assessment of Cancer Therapy-Cognitive Function, Montreal Cognitive Assessment Scale, and Pittsburgh Sleep Quality Index. Results Twenty-six patients in each of the two groups completed the full study.After intervention, the subjective and objective cognitive scores of the experimental group were significantly higher than those of the control group, and the sleep quality scores were significantly lower than those of the control group （P＜0.05 for all）. Conclusion Walking exercise intervention could improve cognitive function and sleep quality in breast cancer chemotherapy patients to a certain extent.