【Abstract】 Objective To investigate the effect of miR-15b targeting lpar3 on the proliferation of endometrial cancer cell line hec1b. Methods Bioinformatics analysis and luciferase reporter gene experiment were used to verify the targeted binding between miR-15b and LPAR3. The HEC-1B cells were divided into NC group, miR-15b mimic group, miR-15b inhibitor group, siRNA-LPAR3 group, and miR-15b inhibitor+siRNA-LPAR3 group. Realtime fluorescent quantitative PCR and Western blot were used to detect miR15b, LPAR3 and the expression levels of PI3K/AKT signaling pathway related factors phosphatidylinositol3kinase (PI3K) and threonine kinase (AKT) in HEC-1B and human endometrial epithelial cells (HEEC). Cell viability of HEC1B was detected by MTT method, cell cycle distribution of HEC1B was detected by flow cytometry, and cell migration and invasion ability of HEC1B was detected by Transwell method. Results LPAR3 was the target gene of miR-15b. Compared with human normal endometrial epithelial cells, LPAR3, PI3K, and AKT mRNA and protein expression levels of HEC-1B were significantly increased (P＜0.05), while miR-15b expressionwas significant reduced (P＜0.05). Compared with NC group, mRNA and protein expression levels of PI3K/AKT signaling pathwayrelated factors in siRNA-LPAR3 group were significantly reduced (P＜0.05). LPAR3 and PI3K/AKT signaling pathway related factors mRNA and protein expression levels in HER-1B cells of miR-15b mimic group were significantly reduced (P＜0.05). Ccompared with the NC group, the cell viability, Sphase cell ratio, migration and invasion ability in siRNA-LPAR3 group were significantly reduced (P＜0.05). The cell viability, Sphase cell ratio, migration and invasion ability of miR-15b mimic group were significantly reduced (P＜0.05). After inhibiting the expression of miR-15b, the above phenomenon was reversed. Compared with the miR-15b inhibitor group, the cell viability, proportion of Sphase cells, migration and invasion ability of the HER-1B in the miR-15b inhibitor+siRNA-LPAR3 group were significantly reduced (P＜0.05). Conclusion miR-15b may inhibit the proliferation of hec1b cells by targeting lpar3 to inhibit the activation of PI3K/Akt signaling pathway of hec-1b.