Objective: To explore the effects of smartphone-based hospital-family transitional care on symptom burden and quality of life in elderly patients with depression. Methods: This study retrospective analyzed the clinical data of 168 elderly patients with depression admitted to our hospital from January 2022 to January 2024. A total of 79 patients were included in the reference group (routine transitional management), and 89 subjects were included in the observation group (smartphone-based hospital-family transitional care). The symptom burden and quality of life in both groups before and after management were compared. The main statistical methods used in this study were the chi-squared test and the Mann-Whitney U test. Results: Before discharge, no significant difference existed in Geriatric Depression Scale (GDS) scores, P300 latency, P300 amplitude, Montreal Cognitive Assessment (MoCA) scores, and the scores of each domain in the World Health Organization Quality of Life (WHOQOL)-BREF between the two groups (all p > 0.05). After 5 months, the observation group demonstrated a significantly lower GDS score (p = 0.016), shorter P300 latency (p < 0.001), higher P300 amplitude (p < 0.001), higher MoCA score (p = 0.001), and significantly higher scores in physiological, psychological, and environmental domains than the reference group (p < 0.001), with no significant difference in social relation domain (p > 0.05). Conclusions: Smartphonebased hospital-family transitional care can improve the symptom burden, cognitive function, and quality of life of elderly patients with depression.