Objective To construct a self-disclosure intervention program for young and middle-aged breast cancer patients based on the Social Cognitive Processing Model and to explore its implementation effects.Methods A self-disclosure intervention program for young and middle-aged breast cancer patients was developed through literature research and expert consultation, grounded in the Social Cognitive Processing Model.Eighty-four young and middle-aged breast cancer patients were divided into a control group and an intervention group, with 42 patients in each group.The control group received routine nursing interventions and follow-ups, while the intervention group received self-disclosure interventions developed based on the Social Cognitive Processing Model in addition to routine care.The levels of self-disclosure, post-traumatic growth, and medical coping strategies were compared between the two groups before and after the intervention.Results A total of 39 patients in the control group and 40 patients in the intervention group completed the study.After the intervention, the intervention group showed significantly higher scores of self-disclosure, post-traumatic growth, and effective medical coping strategies compared to the control group (all P＜0.05).Conclusion The self-disclosure intervention based on the Social Cognitive Processing Model effectively enhances self-disclosure levels among young and middle-aged breast cancer patients, encourages positive coping strategies, promotes post-traumatic growth, and improves emo-tional adjustment in breast cancer patients.