Gastric cancer (GC) is one of the most common malignant tumors in the human digestive system, which seriously affects people's quality of life. As an effective treatment for GC, traditional Chinese medicine can effectively alleviate patients' clinical symptoms, improve the quality of life, and delay the life cycle. A large number of clinical studies have shown that Banxia Xiexin Decoction has shown a good effect in the treatment of GC. It has achieved good curative effect whether it is used alone or combined with radiotherapy and chemotherapy, which may play a more significant role in the treatment of GC. However, there is still no evidence of evidence-based medicine. Therefore, this study aims to systematically evaluate the efficacy and safety of Banxia Xiexin Decoction as a complementary treatment for GC. Two researchers will search the following databases: PubMed, Web of Science, MEDLINE, the Cochrane Library, Embase, China National Knowledge Infrastructure, the Chongqing VIP Chinese Science and Technology Periodical Database, Wanfang Database, and China Biomedical Database. In addition, the Chinese Clinical Trial Register, Chinese Clinical Trial Register, conference papers, and other relevant literature will be searched manually. The retrieval time of these databases is from the establishment of the database to March 2021. The main outcome indicators of this study are the effective rate of treatment and the traditional Chinese medicine syndrome score. According to the inclusion and exclusion criteria of the literature, the data were screened and extracted. The literature quality was evaluated by the bias risk assessment tool of randomized controlled trials recommended by Cochrane Handbook, and meta-analysis was conducted RevMan 5.3 software. The Grading of Recommendations Assessment, Development, and Evaluation will be used to evaluate the quality of evidence. This study will comprehensively review the existing evidence of Banxia Xiexin Decoction as a complementary in the treatment of GC. The conclusion of this study will provide a basis for judging whether Banxia Xiexin Decoction is an effective and safe intervention for GC patients. INPLASY202140060. Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.