Background <p>With the rising survival rates of breast cancer, fertility preservation has become a paramount concern for young patients throughout their anticancer treatment. We conducted a systematic review to assess and synthesize evidence and recommendations on fertility preservation in breast cancer patients to provide evidence-based clinical guidance.</p> Methods <p>According to the ‘6S’ evidence resource model, evidence retrieval is searched from the top-down and collected relevant clinical decisions, guidelines, evidence summaries, expert consensus, recommended practices, and systematic reviews. The retrieval time limit was from the database establishment to July 2025. Two reviewers independently screened and evaluated the literature, and then extracted and summarized the evidence according to the JBI grading of evidence and recommendation system.</p> Results <p>A total of 47 publications were finally included, including 14 guidelines, 9 expert consensus, 7 recommended practices, and 17 systematic reviews. Through the induction and integration of the evidence, the evidence was finally summarized from ten aspects: treatment-related factors for fertility impairment, risk assessment of fertility impairment, genetic risk assessment and intervention, fertility preservation counseling and management, target population for fertility preservation, fertility preservation protocols, surgical treatment and fertility, post-treatment pregnancy management, post-treatment breastfeeding management and contraceptive management, and totally 50 best available evidence were formed.</p> Conclusions <p>This study summarized the best available evidence for fertility preservation in breast cancer patients from ten aspects, which can provide guidance for clinical medical staff to develop individualized fertility preservation plans and assist patients in making fertility preservation decisions, ultimately supporting young breast cancer patients in achieving the dual goals of survival and future parenthood.</p>