Objective To explore the impact of health literacy on health behaviors and outcomes of elderly patients with chronic heart failure (CHF) after discharge from the hospital. Methods A prospective study was conducted on 231 CHF patients.The baseline data were collected before discharge, including demographic variables, disease-related information, and health literacy.Follow-up data were collected 1 month after discharge, including social support, medication adherence, psychological distress, health-related quality of life, and unplanned readmissions.The impact and mediation effect were analyzed. Results Health literacy had direct effect on medication adherence and health-related quality of life, with the direct effects being 0.281 and -0.290 respectively, and also had indirect effect through social support and psychological distress.The 30-day unplanned readmission rate was 14.29%.Health literacy had a protective effect on unplanned readmission, with the direct effect being -0.304, and also indirectly affected unplanned readmission via social support and psychological distress （indirect effect coefficients being -0.128 and -0.115 respectively）. Conclusion Health literacy is a protective factor for health behavior and outcomes of CHF patients.Medical staff need to take effective interventions to improve patients′ health literacy, thus to enhance their health behavior and avoid unplanned readmission.