Background: Postoperative lymphedema is a chronic complication that impairs quality of life (QoL) in breast cancer survivors. Preventive behaviors are key to mitigation, but their relationship with QoL in high-risk populations requires further investigation. Patients and Methods: A cross-sectional study enrolled 276 high-risk post-surgical breast cancer patients. A self-developed preventive behavior questionnaire and the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30) were used. Data were analyzed with correlation and multivariate regression. Results: Overall preventive behavior scores were moderate-to-low, with poorest adherence in skin care and exercise. A significant positive correlation was found between the total preventive behavior score and total QoL score ( r = 0.45 and P < .01). Regression analysis confirmed that better preventive behaviors significantly predicted higher QoL, particularly in functional and emotional domains ( P < .05). Conclusion: Preventive behavior adherence is significantly associated with QoL in high-risk patients. Enhancing behaviors-especially skin care and exercise -can improve QoL. Targeted education and personalized intervention strategies are recommended.