As the global incidence of breast cancer continues to surge, the pursuit of novel, low-toxicity, and highly efficacious therapeutic strategies has emerged as a pivotal research focus. Curcumin (CUR), an active constituent of traditional Chinese medicine (TCM) renowned for its antimicrobial, anti-inflammatory, antioxidant, and antitumor properties, exhibits immense potential in breast cancer therapy. Nevertheless, CUR's poor water solubility, chemical instability, and unfavorable pharmacokinetics have impeded its clinical utilization. To address these challenges, nano-delivery systems have been extensively exploited for CUR administration, enhancing its in vivo stability and bioavailability, and facilitating precise targeting of breast cancer lesions. Therefore, we elaborate on CUR's chemical foundations, drug metabolism, and safety profile, and elucidate its potential mechanisms in breast cancer therapy, encompassing inducing apoptosis and autophagy, blocking cell cycle, inhibiting breast cancer metastasis, regulating tumor microenvironment and reversing chemotherapy resistance. The review primarily emphasizes recent advancements in CUR-based nano-delivery systems for the treatment and diagnosis of breast cancer. Liposomes, nanoparticles (encompassing polymer nanoparticles, solid lipid nanoparticles, mesoporous silica particles, metal/metal oxide nanoparticles, graphene nanomaterials, albumin nanoparticles, etc.), nanogels, and nanomicelles can serve as delivery carriers for CUR, exhibiting promising anti-breast cancer effects in both in vivo and in vitro experiments. Furthermore, nano-CUR can be integrated with fluorescence imaging, magnetic resonance imaging, computed tomography imaging, ultrasound, and other techniques to achieve precise localization and diagnosis of breast cancer masses. While this article has summarized the clinical studies of nano-curcumin, it is noteworthy that the research literature on nano-CUR applied to breast cancer diagnosis and the translation of nano-CUR clinical studies in BC patients remain limited. Therefore, future research should intensify exploration in this direction.