Cysteine protease inhibitor 1 (CST1) is a member of type 2 Cystatins superfamily, plays a key role in targeted regulation. CST1 is highly expressed in gastric cancer, promotes tumor cell migration and invasion by activating the epithelial-mesenchymal transformation pathway and Wnt pathway, and regulates tumor growth and progression in combination with the corresponding target genes of homeobox C10 and glutathione peroxidase 4. A deeper understanding of the role and function of CST1 in gastric cancer will help to further develop potential therapeutic targets and diagnostic and prognostic markers for gastric cancer.