Objective To screen the key Mutation Genes in endometrial adenocarcinoma and study the relationship between their expression and immune response and prognosis. Methods The data of 543 cases of endometrial adenocarcinoma and 177 cases of normal tissues were downloaded from the Cancer Genome Atlas (TCGA) and genotype tissue expression (GTEX) for bioinformatics analysis. 22 cases of endometrial adenocarcinoma were collected, RT-qPCR was used to verify the gene expression. Results More than 96.38% of the patients had mutations, including missense mutation, single nucleotide mutation and C>T mutation. The top 10 mutations were PTEN, PIK3CA, TTN, ARID1A, TP53, MUC16, PIK3R1, KMT2D, CTCF and CSMD3. In TCGA, the expression of TP53 mutant was significantly higher than that of wild type (P<0.0001). The expression of TP53 in cancer tissue was higher than that in normal tissue, and the expression of TP53 mutant was higher than that of wild type (P<0.05). The overall survival (OS), progression free survival (PFS), disease free survival (DFS) and disease free survival (DSS) of TP53 mutant were lower than those of TP53 wild type (P<0.0001, P<0.0001, P=0.001, P<0.0001). A total of 344 differentially expressed genes (195 up-regulated and 149 down regulated) were identified in wild-type and mutant TP53. Compared with the wild type, the mutant was negatively enriched in the ^“immune effector process^”, ^“immune response^”, ^“immune system progress^”, ^“innate immune response^” and ^“immune response regulation^” pathways (P=0.001). The scores of T cell CD8 +, neutrophil, macrophages and meyloid dendritic cells of TP53 mutant were lower than those of wild type. Conclusion TP53 is highly expressed in endometrioid adenocarcinoma, and the expression of mutant is higher than that of wild type. TP53 mutation is positively correlated with poor prognosis and can inhibit immune response.