Objective To observe and analyze the clinical effect of carotid endarterectomy on severe internal carotid artery stenosis. Methods From March 2018 to March 2021, a total 120 cases of internal carotid artery stenosis admitted to the Department of Neurosurgery of Xinjiang Yining Corps Fourth Division Hospital were selected as study subjects and randomly divided into a control group （n = 60, carotid artery stenting） and an observation group （n = 60, carotid endarterectomy）. Cognitive function after operation, quality of life, clinical efficacy, and postoperative complications were compared between the two groups. Results Before treatment, there were no significant differences in WHOQOL-BREF score and MoCA score between the two groups （P>0.05）. After treatment, the WHOQOL-BREF score and MoCA score of the two groups were improved significantly, and the scores in the observation group were significantly higher than those in the control group （P<0.05）. The total clinical effective rate in the observation group was significantly higher than that in the control group （P<0.05）. The total incidence rate of complications in the observation group was significantly lower than that in the control group （P<0.05）. Conclusion Carotid endarterectomy shows an obvious clinical effect on severe internal carotid artery stenosis; it can significantly improve patients’ carotid artery blood supply, cognitive function, and quality of life.