Objective: To systematically evaluate the efficacy of use of pseudomonas aeruginosa (PA) preparation in treatment of breast cancer. Methods: The randomized controlled trials (RCTs) concerning the use of PA preparation in treatment of breast cancer were collected by searching the national and international databases, and the time period of search ranged from inception of each database until November 2014. After literature screening, data extraction and quality assessment, Meta-analysis was performed by Revman 5.1.2 software. Results: Nine RCTs were finally included. The results of Meta-analysis showed that combined use of PA preparation with conventional treatment significantly increased the complete response rate (OR=2.22), total response rate (OR=6.73), Karnofsky score (MD=9.79) and IL-2 level, and significantly decreased the stable disease rate (OR=0.36) and progress disease rate (OR=0.18), as well as shortened the time to disappearance of the postoperative fluid collection (MD=–7.52). Conclusion: Combined use of PA preparation can increase the efficacy of conventional chemoradiotherapy in treatment of breast cancer, but this conclusion needs further verification by more high quality studies.