Objective To study the effect of 3+1 rehabilitation nursing mode on treatment effect and cognitive function of dementia patients. Methods Two hundreds and forty cases of dementia patients were randomly divided into the observation group and the control group with 120 cases in each group. The observation group were treated with routing therapy and 3+1 nursing mode and the control group with routine therapy and nursing. Mini-mental state examination(MMSE), and main symptoms (MS) scales,activity of daily living (ADL) scale were used for assessment of symptoms and signs before and after nursing. Results Changes of scores for MMSE, MS and ADL before and after rehabilitation nursing had statistical differences in the two groups. Conclusions The 3+1 nursing mode can improve the effect on cognitive function of dementia patients.