Background: We demonstrated that drinking hydrogen-rich water (HRW) inhibits endometrial tumor growth in our previous work. This research is to identify differentially expressed proteins (DEPs) between HRW and purified water groups in a xenograft mouse model of endometrial cancer (EC).Methods: Samples were analyzed using tandem mass tags (TMTs) coupled with liquid chromatographytandem mass spectrometry (LC-MS/MS). DEPs were identified using bioinformatics to determine potential molecular functions and immunohistochemical (IHC) staining.Results: In total, 11 DEPs were identified in the HRW group relative to the control. The up-regulated proteins included Gatad1, Ttyh3, Nek4, Dyrk2, and Gimap1, while the down-regulated proteins included SP1, Msl1, Plekha7, Dtwd2, MSRA, and KRAS. Gene Ontology (GO) annotations and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were associated with the binding region, biological regulation, endocrine resistance, estrogen signaling, choline metabolism in cancer and human cytomegalovirus infection. Furthermore, network analysis indicated that KRAS and MSRA interact with YWHAE. KRAS, YWHAE and SP1 were strongly expressed, while MSRA was weak expressed in atypical hyperplasia and EC tissue as well as in HRW group in xenograft tumor tissue.Conclusions: KRAS, YWHAE, SP1 and MSRA might be regarded as focused biomarkers to assess the prognosis of EC.