Endometrial cancer (EC) is one of the predominant tumors of the female reproductive system. In this current study, we investigated the functions and related mechanisms of NAP1L1/DDX5 in EC. This retrospective study analyzed the medical records of EC patients, collected tissue samples for NAP1L1 and DDX5 staining, and conducted survival analysis using the Kaplan-Meier method. To evaluate the impact of NAP1L1 and/or DDX5 on cellular processes in EC cells, several techniques were employed. These included CCK-8 assay, wound healing assay, Transwell assay, as well as overexpression or knockdown of target gene expression. Additionally, ChIP, dual luciferase reporter gene, Co-IP assay were utilized to confirm the interaction between NAP1L1, EP300 and DDX5. Furthermore, qRT-PCR, western blot and Co-IP assay were performed to analyze the modulation of NAP1L1/DDX5 in Wnt/β-catenin. NAP1L1 and DDX5 expression were upregulated in EC tissues, and correlated with poor prognosis. NAP1L1/DDX5 promoted EC cell proliferation, migration and invasion. NAP1L1 promotes acetylation and transcription by recruiting EP300 to the DDX5 promoter. DDX5 could activate Wnt/β-catenin signal by binding to β-catenin. In animal models, knockdown of NAP1L1 inhibits EC tumor growth and lung metastasis. To sum up, our study demonstrated that NAP1L1 promoted the malignant phenotypes of EC cells via recruiting EP300 to promote DDX5 acetylation, thus activating the Wnt/β-catenin signaling pathway. Implications: Our research findings indicate that targeting the NAP1L1/EP300/DX5 axis might be a new potential treatment option for endometrial cancer.