BackgroundThis study explores the influence of family function on depression in older adults with chronic comorbidities and the mediating roles of cognitive fusion and coping styles.MethodsThe Family Adaptation Partnership Growth Affection and Resolve Index, Patient Health Questionnaire‐9, Cognitive Fusion Questionnaire‐Fusion, and Trait Coping Style Questionnaire were used to survey 448 community‐dwelling older adults with chronic comorbidities. A mediation test was conducted using the Process 4.0 macro program.ResultsFamily function was found to be significantly and negatively correlated with cognitive fusion, maladaptive coping style, and depression. Cognitive fusion and maladaptive coping style were positively correlated with depression. Cognitive fusion was positively correlated with maladaptive coping styles. Family function affected depression directly; it also affected older adults' depression through two indirect paths: through the mediating role of cognitive fusion and the chain‐mediating role of both cognitive fusion and maladaptive coping style.ConclusionsFamily function in older adults can influence their levels of depression, which is mediated by cognitive fusion and maladaptive coping styles. Based on these findings, interventions to prevent and alleviate depression in older adults with chronic disease comorbidities can be offered to improve their well‐being.