Background: Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death worldwide in women. Both Talazoparib and Olaparib are approved by FDA for BRCA mutated HER2-negative metastatic or advanced breast cancer patients. However, the optimal choice of first-line treatment is not still determined. Objective To compare the efficacy, safety and acceptability of single-agent PARP inhibitors for BRCA mutated HER2-negative metastatic or advanced breast cancer patients. Methods: We did a systematic review and network meta-analysis. A systematic search of Web of Science, Embase, PubMed, Medline, ClinicalTrials.gov, the Cochrane Central Register of Controlled Trials, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and international registers for published and unpublished, double-blind, randomized controlled trials from their inception to July 20, 2019. This study is registered with PROSPERO (CRD42019138939). Results: We identified 2 citations and included 2 trials comprising 733 participants. Compared with Talazoparib, Olaparib was not associated with improved PFS (HR=1.08, 95% CrI=0.34-3.45) as well as OS (HR=1.18, 95% CrI=0.61-2.31). Compared with Talazoparib, Olaparib may be associated with insignificantly improved ORR (OR=0.83, 95% CrI=0.05-12.64). In terms of the results of safety, compared with Talazoparib, Olaparib had reduced risk of anaemia both for adverse events of 3-4 grade (OR=0.34, 95% CrI=0.003-34.94) and any grade (OR=0.37, 95% CrI=0.02-6.81). In addition, Olaparib also showed a low risk of neutropenia for adverse events of 3-4 grade (OR=0.57, 95% CrI=0.06-5.75) compared with Talazoparib. Both Talazoparib and Olaparib were not associated with high risk of treatment discontinuation (OR=0.95, 95% CrI=0.21-4.47). In terms of the time to deterioration in QoL, compared with Talazoparib, Olaparib may be associated with short time to clinically meaningful deterioration in QoL (HR=1.16, 95% CrI=0.19-7.17). Conclusion: Both Talazoparib and Olaparib confered similar efficacy, safety and acceptability in patients with BRCA-mutated HER2-negative metastatic or advanced breast cancer.