Abstract Background: Thrombopoietin (THPO) is a protein that could mediate megakaryocyte growth and development. It participates in some cellular processes such as megakaryocyte proliferation and maturation. However, the role of THPO in gastric adenocarcinoma still remain unknown. Materials and methods: The TCGA database supplied to predict THPO expression level in gastric adenocarcinoma initially. Prognostic significance of THPO and association between THPO expression and clinical features were described by Kaplan-Meier as well as Cox regression analysis. Subsequently, siRNA method was used to inhibit THPO expression and then cell proliferation, clone formation, invasion and migration were performed to measure the effects of knockdown THPO on cell behaviors. The qRT-PCR and western blotting assays were implemented to measure the expression level. Results: The expression of THPO was increased in tumor tissue and cells, its high-regulation was implicit to poor prognosis. After knockdown THPO, cell proliferation, clone formation, invasion and migration were suppressed in AGS. Furthermore, E-cadherin was promoted, N-cadherin and Vimentin were attenuated through western blot. Conclusion: Our results revealed that THPO may be a potential biomarker and therapeutic target in gastric adenocarcinoma, providing new light on tumor progression.