Background: The STEAP family is crucial in the control of metal homeostasis. A increasing amount of data suggests the link between epigenetic alterations in the STEAP family and a range of human malignancies. Nevertheless, the STEAP family's significance in gastric cancer is unclear, and there are few relevant research.Bioinformatics analysis was carried out using R software, Kaplan-Meier Plotter, cBioPortal, TIMER, LinkedOmics, STRING, Metascape, and GSCA Lite online tools.The expression of STEAP1/2/3 was dramatically upregulated in numerous tumor tissues, in particular, gastric cancer, but STEAP4 expression was significantly downregulated. Poor treatment results and aggressiveness of cancer are associated with high STEAP1/2/3 expression.Pathway analysis of the STEAP family and its co-expressed genes using Gene Ontology (GO) and Kyodo Encyclopedia of Genes and Genomes (KEGG) revealed that numerous gene terms were related with "iron ion homeostasis," "copper ion transport," "response to iron ion," and "iron ion transport." "response to iron ion," "oxidoreductase activity acting on metal ions," and "ion transport" The pathways are associated with "iron ion homeostasis," "copper ion transport," "react to iron ion," and "oxidoreductase activity involving metal ions."Notably, there was a positive correlation between STEAP 1/2/3 expression levels and oxidative stress genes,such as NOX3 and NOX4. PPI network analysis revealed that STEAP family proteins strongly interacted with TFRC. In addition, STEAP 1/2/3 expression was linked with B-cell, CD8+ T-cell infiltrating immune lymphocytes. Interestingly, Overexpression of STEAP 1/3 was also linked to decreased susceptibility of gastric cancer cells to a number of gastric cancer-targeting or chemotherapeutic drugs, including Docetaxel and Vorinostat. STEAP family members may be prognostic indicators and novel treatment targets for patients with gastric cancer.