Gastric cancer is the leading cause of cancer-related mortality. Targeted drug therapy is one of the most important therapeutic means for gastric cancer. Human epidermal growth factor receptor 2 (HER2) is an important therapeutic target for gastric cancer. Trastuzumab is a monoclonal antibody that targets HER2. The ToGA trial has established trastuzumab in combination with chemotherapy as the standard treatment for patients with HER2-positive advanced gastric cancer. This article reviews the progress in ToGA experiment, trastuzumab combined with other chemotherapy drugs, trastuzumab combined with other HER2-targeted drugs, trastuzumab and other drug conjugate, and trastuzumab combined with other targeted drugs in the treatment of HER2-positive advanced gastric cancer. Trastuzumab combined with S-1 and other chemotherapeutic drugs has shown good efficacy and safety; the combination of pertuzumab and trastuzumab did not meet the primary endpoint; trastuzumab emtansine (T-DM1) showed no benefit in improving overall survival in patients with HER2-positive advanced gastric cancer. KN026, trastuzumab deruxtecan (T-DXd), Trastuzumab and Pembrolizumab combined chemotherapy, as well as bevacizumab and trastuzumab combined with capecitabine and oxaliplatin are the most progress research advances in the treatment of HER2-positive advanced gastric cancer.