This study aims to develop and evaluate a smart nursing AI agent to support health self-management among middle-aged and older patients, and further to examine its effectiveness in home care and health self-management. The goal is to propose innovative strategies for middle-aged and older care that enhance the quality of home care and strengthen patients' health self-management abilities. A randomized controlled trial design will be adopted, with a planned enrollment of 102 participants. Participants will be randomly assigned to either the experimental group or the control group. Regardless of group assignment, their routine medical care will remain unchanged. Both groups will participate in the study for 12 weeks (8 weeks of intervention and 4 weeks of follow-up), with identical frequency and number of follow-ups, interviews, and evaluations. The experimental group will receive an 8 week intervention using the smart nursing AI agent care model, which provides daily interaction, reminder systems, personalized recommendations, activity monitoring, goal setting, motivational support, and health self-management education. The control group will continue with the existing standard health education approach. Data collection will include demographic information, medical history, physiological indicators, functional activity measures (e.g., steps, distance, exercise duration), sarcopenia screening, nutritional assessment, physical activity levels, health self-management ability, health literacy, quality of life, and digital usage behaviors. Statistical analyses will be conducted to evaluate the effectiveness, feasibility, and acceptability of the intervention.