MicroRNA miR-302 has been found to induce some tumor cell lines to “transdifferentiate” into miRNA-induced pluripotent stem cells (mirPS), thereby inhibiting tumor cell proliferation and reducing tumorigenicity. This study firstly found that miR-302 inhibited the proliferation and migration of endometrial cell line, Ishikawa and HEC-1-B, and arrested cell cycle at the G2/M phase. In addition, miR-302 inhibited tumorigenicity in immunodeficient mice transplanted with Ishikawa cells. Microarray and Western blotting results showed that miR-302 significantly inhibited CDK1 and Cyclin D1 gene expression in Ishikawa cells. MiR-302 directly targeted Cyclin D1, but indirectly regulated CDK1 gene expression.