To explore the effects of high and low expression of HMGA2 on immune infiltration and ferroptosis in gastric cancer(GC), the transcriptome datasets of GC were download from TCGA and GEO databases. Tumor immune cell infiltration was analyzed using various immune infiltration algorithms in the TIMER2.0 database. Differential expression genes were screened using the DESeq2 R package. The relationship between HMGA2 and GC ferroptosis was analyzed based on the FerrDb V2 database. The expression of HMGA2 is found to be correlated with the infiltration of CD8 + T cells, CD4 + T cells, B cells, and neutrophils in GC. Significant differences in immune cell infiltration levels are observed between GC with high and low HMGA2 expression. Abnormal expression of HMGA2 is suggested to influence cancer-related biological processes and pathways, including calcium ion binding, chloride transport, steroid hormone biosynthesis, and cholesterol metabolism in GC. Additionally, the expression levels of TF and SALL4 are found to differ significantly between the high and low HMGA2 expression groups, and both are strongly positively correlated with HMGA2 expression. Kaplan-Meier survival analysis is performed and reveals that GC patients with high expression of TF or SALL4 are associated with poor prognosis. Furthermore, the expressions of TF and SALL4 are significantly associated with immunity and ferroptosis in GC. In summary, the high and low expression of HMGA2 are considered to exert distinct effects on immunity and ferroptosis in GC, which contributes to a deeper understanding of its molecular mechanisms and provides guidance for the development of more precise and effective therapeutic strategies for different subtypes of GC patients.