Depression and anxiety are associated with higher incidence of tumors, cancer-specific mortality, and all-cause mortality. Compared with patients with other types of cancer, breast cancer patients often accompany physical damage, changes in physiological status, decline in quality of life, sensitivity in interpersonal relationships, and side effects of drug treatment during the occurrence, development, and treatment of cancer, leading to long-term chronic mental stress. The prevalence of depression and anxiety in early-stage breast cancer patients in China is as high as 44.1% and 35.2%, respectively. A meta-analysis based on 282,203 breast cancer patients suggests that depression is related to breast cancer-specific mortality, and patients with breast cancer and depression have a poorer prognosis. Intervention in response to stressors may improve psychological and physiological adaptation processes and even benefit quality of life and clinical health outcomes. More and more randomized controlled trials focus on improving the quality of life and adverse reactions of cancer patients after stress management, but there are few reports on the direct improvement of anti-tumor efficacy. Therefore, we plan to conduct a small sample, exploratory, randomized controlled study to clarify the impact of transcranial direct current stimulation (tDCS) intervention on the efficacy of neoadjuvant chemotherapy in breast cancer patients with depressive symptoms. Newly diagnosed breast cancer patients will be assessed for emotions by mental health professionals, with a PHQ9 score of 5-14 and ≥ 5 symptoms considered positive, combined with enrollment criteria for screening. Patients who meet the enrollment criteria will be randomly divided into the control group (i.e., supportive psychotherapy group) and the experimental group (i.e., tDCS + supportive psychotherapy group). The primary study endpoint is the objective remission rate (ORR) of neoadjuvant treatment. This study aims to improve the depressive state of breast cancer patients undergoing neoadjuvant chemotherapy through physical therapy (tDCS) and to clarify whether there is a correlation between emotional intervention and neoadjuvant efficacy.