Objective To investigate the heterogeneous trajectories of depression among institutionalized elderly persons and to identify the predictive effect of activities of daily living (ADL). Methods A longitudinal study was conducted on 296 institutionalized elderly persons, using the Barthel Index (BI),Patient Health Questionnaire-2 (PHQ-2) and Lubben Social Network Scale (LSNS) to collect their ADL level,depression and social support, at baseline assessment. Then they were followed up 6 and 12 months later and measured for depression intensity. Results The prevalence of depression among the subjects was 14.9% at baseline assessment, 20.9% at 6-month follow-up and 17.2% at 12-month follow-up. Two different depression trajectories were identified in 250 subjects who completed two assessments:high-risk deterioration (14.8%) and low-risk deterioration (maintenance,85.2%). Age, occupation, and ADL score were predictors of depression trajectory (P<0.05, P<0.01). Conclusion Institutionalized elderly persons showed distinct trajectories of depression, and low ADL level might deteriorate their depression. It is necessary to strengthen ADL training for institutionalized elderly persons, thus to reduce the incidence of depression.