Objective: The objective of this study is to evaluate the efficacy prediction values of systemic immune-inflammation index (SII) and prognostic nutritional index (PNI) in breast cancer patients who received neoadjuvant chemotherapy.Methods: We registered a retrospective study include 72 breast cancer patients between February 2020 and January 2022. All patients had axillary lymph node metastasis receiving neoadjuvant therapy. Calculating PNI, SII before and after therapy were examined through blood routine. Chi-square test was used to compare the clinicopathological and laboratory parameters between groups. Using the logistic regression analysis to evaluate the prognosis values of the factors.Results: 18 patients (25%) achieved pathologic complete response (pCR) after neoadjuvant therapy. The pCR rate of breast patients had significant relationship with ER, PR, HER-2, molecular subgroup, tumor size, vascular invasion, nerve invasion, N stage, clinical stage and chemotherapy regimen. Low ΔPNI, high ΔSII and higher ΔPNI-ΔSII score values had better prediction of therapeutic effect, especially the ΔPNI-ΔSII score.Conclusion: The ΔPNI-ΔSII score may be an effective efficacy prediction index in breast cancer patients receiving neoadjuvant chemotherapy, which can help to identify high-risk groups and efficacy evaluation.