Recent studies suggest that the human microbiome influence tumor development. Endometrial carcinoma (EC) is the sixth most common malignancy in women. Recent research has demonstrated the microbes play a critical role in the development and metastasis of EC. However, it remains unclear whether intratumoral microbes are associated with tumor microenvironment (TME) and prognosis of EC. In this study, we collected the EC microbiome data from cBioPortal and constructed a prognostic model based on Resident Microbiome of Endometrium (RME). We then examined the relationship between the RME score, immune cell infiltration, immunotherapy-related signature, and prognosis. The findings demonstrated the independent prognostic value of the RME score for EC. The group with low RME scores had higher enrichment of immune cells. Drug sensitivity analysis revealed that the RME score may serve as a potential predictor of chemotherapy efficacy. In conclusion, our research offers new perspectives on the relationships between tumor immunity and microbes.