Aims: The study aims to investigate the clinical characteristics of patients with negative sentinel lymph node biopsy (SLNB) results among those with low-risk early-stage breast cancer, providing evidence for criteria to exempt certain patients from SLNB. Methods: A retrospective observational study was conducted on patients with early-stage breast cancer (cT0-2 N0-1 M0) from January 2015 to December 2020. Patients were categorized into negative and positive groups based on their SLNB results. The clinical data collected included demographics, imaging findings, clinical stage, pathological information, and treatment outcomes. Results: Out of 385 patients, 252 had negative SLNB. Risk factors for negative SLNB included being under 40 years old, ductal carcinoma in situ (DCIS), early clinical staging, smaller tumor diameters (<2 cm), higher levels of estrogen receptor (ER) and progesterone receptor (PR) expression, negative Her-2 status, and lower Ki67 expression. Multivariate analysis revealed that positive lymph nodes from MRI correlated with higher rates of axillary lymph node metastasis, with MRI-detected positive findings being a significant risk factor for postoperative recurrence and metastasis. There was no significant difference in disease-free survival (DFS) time between the negative and positive SLNB groups. Conclusions: SLNB may not be necessary for early-stage breast cancer patients under 40 with tumors smaller than 2 cm, DCIS, positive ER and PR expression, and negative MRI findings. MRI was emphasized as a critical tool for predicting lymph node metastasis and assessing patient prognosis.