Objective To explore the effect of extended dialysis time on cognitive function in maintenance hemodialysis patients.Methods A total of 40 patients with maintenance hemodialysis in Shouguang Hexin Hospital from March 2021 to June 2022 were selected as the research objects.According to the random number table method,they were divided into control group (20 cases)and observation group (20 cases).The control group was treated with hemodialysis for 4 hours each time,and the observation group was treated with extended hemodialysis for 5 hours each time.Both groups were treated for 6 months.The cognitive function (Montreal cognitive assessment [MoCA])and quality of life (quality of life questionnaire[QLQ-C30])were compared between the two groups before treatment and 6 months after treatment.Results After 6 months of treatment,the scores of each item and the total score of MoCA scale in the observation group were higher than those in the control group,and the differences were statistically significant (P＜0.05).The QLQ-C30 scores of the observation group were higher than those of the control group after 6 months of treatment,and the differences were statistically significant(P＜0.05).Conclusion Extending the dialysis time of maintenance hemodialysis patients is beneficial to improving the cognitive function of patients and improving the quality of life.