Background. Guanylate cyclase 1 soluble subunit alpha 2 (sGCα2), also known as GUCY1A2, was reported to be upregulated and promoted tumorigenesis in cervical cancer. But whether GUCY1A2 was abnormally expressed and its prognostic value in gastric cancer was unknown. The current study aimed to find out the prognostic value of GUCY1A2 in gastric cancer by analyzing data from The Cancer Genome Atlas (TCGA) database. Methods. Wilcoxon signed-rank test, cox regression analysis and multivariant analysis were used to analyze the relationship between clinical characteristic and GUCY1A2 expression level. Kaplan-Meier method was used to analyze the association of GUCY1A2 and overall survival. Gene set enrichment analysis (GSEA) was used to identify GUCY1A2-related signaling pathway. Results. Compared to normal tissue, expression of GUCY1A2 was significantly increased in gastric cancer (p<0.001). Increased GUCY1A2 was associated with advanced T stage (p=0.012) and poor survival (p=0.022). Univariate analysis showed that high GUCY1A2 expression was associated with a poor overall survival (HR:1.44, 95% confidence interval [CI]: 1.03-2.02, p=0.03). Multivariate analysis indicated that GUCY1A3 remained an independent prognostic predictor of overall survival (HR:1.75, 95% confidence interval [CI]: 1.20-2.56, p=0.00). GSEA revealed that calcium signaling pathway, MAPK signaling pathway, TGF-β signaling pathway and Wnt signaling pathway were enriched in GUCY1A2 high expression phenotype. Conclusions. GUCY1A2 maybe a potential prognostic predictor of poor survival in gastric cancer. But it need to be further validated clinically.