Objective:To explore the application effect of Internet-based hospital-institution linkage care management model in elderly care for the elderly of dementia.Methods:The research was a quasi-experiment study. A total of 80 elderly people of dementia from three combined medical and nursing institutions, Beijing Fangshan District Mental Health Care Hospital, Beijing Jinhai Hospital of Traditional Chinese Medicine, and Beijing Yiciyuan Nursing Care Center, were selected as the research objects by convenient sampling. The elderly people of dementia enrolled from May to August 2021 served as the control group, and elderly people of dementia enrolled from September to December 2021 served as the experimental group, with 40 cases in each group. Conventional management methods were taken in the control group, while Internet-based hospital-institution linkage care management model was taken in the experimental group. Before the intervention, at 3 months of intervention, the Mini-Mental State Examination (MMSE), Barthel index (BI) and Cohen Mansfield agitation behavior inventory (CMAI) were used to evaluate the cognitive function, activities of daily living and agitation behavior of two groups.Results:A total of 78 cases were included, including 39 cases in the experimental group and 39 cases in the control group, respectively. Before intervention, there was no significant difference in scores of MMSE, BI, and CMAI in the two groups of elderly people with dementia ( P>0.05). After 3 months of intervention, the score of MMSE in the experimental group was (17.36±5.67) points, which was higher than (15.05 ± 2.70) points of the control group, and the difference was statistically significant ( t=2.13, P<0.05). The score of CMAI in the experimental group was (34.18 ± 4.37) points, which was lower than (37.13 ± 5.06) points of the control group, and the difference was statistically significant ( t=2.76, P<0.05). There was no significant difference in BI scores ( t=0.13, P>0.05). Conclusions:The Internet-based hospital-institution linkage care management model improves the cognitive function and agitated behavior of the elderly with dementia in medical-nursing institutions.