Gastric cancer (GC) is one of the most common malignant tumors of the digestive system in China. With the progress of immunotherapy research, programmed death receptor-1 (PD-1) inhibitor-based combinatory therapy offers new ideas for the treatment of advanced gastric cancer. In recent years, with the increasing status of immunotherapy in the treatment of advanced gastric cancer, a growing number of domestic and international clinical studies shown that immunotherapy could achieve better efficacy in the neoadjuvant therapy and conversion therapy for patients with advanced gastric cancer. This paper reviews the current research progress on the application of PD-1 inhibitors in the neoadjuvant therapy and conversion therapy of gastric cancer.