Background <p>Positive psychology suggests combining negative and positive emotions for research, which is beneficial for promoting mental health. Depression is frequently reported among older patients with chronic non-communicable diseases. This study aimed to analyze the status and influencing factors of depression in hospitalized older patients undergoing chronic non-communicable diseases and explore the relationships between alexithymia (negative emotion) and post-traumatic growth (positive emotion) on depression (negative emotion).</p> Methods <p>We conducted a cross-sectional survey using simple random sampling of hospitalized older patients with chronic non-communicable diseases admitted to three tertiary hospitals in Changsha from November 2023 to February 2024. The data were collected by the questionnaire consisting of demographic characteristics, Self-rating Depression Scale, twenty-item Toronto Alexithymia Scale, and Post-traumatic Growth Inventory. We then performed statistical analyses and constructed structural models.</p> Results <p>A total of 321 hospitalized geriatrics with NCDs were surveyed, of whom 77.88% were diagnosed with depression. Self-care ability and post-traumatic growth are protective factors against depression, while alexithymia is a risk factor that has been linked to higher levels of depressive symptoms. In addition, alexithymia mediated the relationship between post-traumatic growth and depression, and post-traumatic growth also played a mediating role between alexithymia and depression.</p> Conclusions <p>During hospitalization, the depression situation of older patients with chronic non-communicable diseases is very serious. Alexithymia and post-traumatic growth not only directly affect depression, but also play an intermediary role in indirectly affecting depression. Medical staff should enhance patients’ emotional regulation and expression, promote post-traumatic recovery, and thereby improve their depressive psychology.</p>