Objective To systematically evaluate the efficacy and safety of dose-dense neoadjuvant chemotherapy (ddNACT) and conventional neoadjuvant chemotherapy (cNACT) for locally advanced breast cancer (LABC). Methods PubMed, Embase, Web of Science, CNKI, Wanfang Data, and VIP databases were searched for randomized controlled trials (RCT) comparing ddNACT regimen with cNACT regimen for breast cancer. The time limit for retrieval was from establishment to March 1st, 2021. Two reviewers independently screened literatures, extracted data and assessed risk bias of included studies; then, meta-analysis was performed by using Stata 15.0 software. Results A total of 13 RCTs were included, including 3 258 patients, of which 1 625 patients received ddNACT and 1 633 patients received cNACT. The results of meta-analysis showed that the ddNACT regimen could improve the pathological complete response rate (pCR, P<0.001), objective response rate (ORR, P<0.001), and disease free survival (DFS, P=0.037) as compared with the cNACT regimen, there was no significant difference in the overall survival (OS) between the two groups (P=0.098). The incidences of grade 3 or 4 oral stomatitis (P=0.005) and neurotoxicity (P<0.001) were higher and the incidence of grade 3 or 4 neutropenia was lower (P=0.025) in the patients with ddNACT regimen, there were no significant differences in grade 3 or 4 thrombocytopenia (P=0.152), grade 3 or 4 anemia (P=0.123), chemotherapy completion rate (P=0.161) and breast conservative surgery rate (P=0.186) between the two groups. Patients with hormone receptor (HR) negative (HR–) were more likely to get pCR after neoadjuvant chemotherapy (P<0.001). ConclusionsCurrent evidence shows that the use of anthracycline/taxane-based ddNACT regimen in LABC patients can improve the pCR, ORR, and DFS as compared with cNACT regimen. The pCR after neoadjuvant chemotherapy in the patients with HR– is higher than that with HR+. Prophylactic use of granulocyte-colony stimulating factor could significantly reduce the incidence of neutropenia, and most patients are tolerant to ddNACT regimen, 2 regimens have similar chemotherapy completion rates.