【Abstract】 Objective To investigate the effect of trastuzumab combined with paclitaxel on serum carcinoembryonic antigen (CEA), carbohydrate antigen (CA125) and carbohydrate antigen (CA153) in patients with metastatic breast cancer. Methods 80 patients with metastatic breast cancer in our hospital from March 2014 to March 2016 served as the research objects. The clinical data were retrospectively analyzed in this study. The patients were divided into observation group and control group. The observation group (40 patients) was treated with trastuzumab combined with paclitaxel treatment. The control group (40 patients) were treated with simple trastuzumab The serum CEA, CA125 and CA153, the influence of shortterm clinical efficacy and adverse reaction conditions were analyzed. Results Serum CEA, CA125 and CA153 levels of the two groups before and after treatment were significantly different. The serum CEA, CA125 and CA153 levels of the observation group after treatment were significantly lower than that of the control group (P<005). The efficiency rate of observation group (70%) was significantly higher than that of the control group (475%) (P<005). The adverse reactions included rash, nausea and vomiting, neutropenia and diarrhea. The incidence of the adverse reaction rate in the observation group and the control group were 325% and 275% (P> 005).Conclusion The trastuzumab in combination with paclitaxel can effectively reduce serum CEA, CA125 and CA153 levels of patients with metastatic breast cancer, play a synergistic effect, have less side effects and reduce the risk of adverse events.