Objective To explore the effects of miR-124-3P on the proliferation and invasion of placental trophoblasts during preeclampsia by targeting MAPK 14. Methods Preeclampsia rat models were established, followed by extraction of placental trophoblast tissue and primary cells from normal rats and model rats. Primary cells were manipulated by transfections. The MTT assay was used to determine cell viability; flow cytometry was used to detect apoptosis and cell cycle arrest; Transwell was used to determine the cell migration and invasion ability, and qRT-PCR and western blotting were used to determine the expression of miR-124-3P and MAPK 14 as well as the expression level of migration-related genes. Verify the binding relationship between miR-124-3P and MAPK 14. Results Compared with the control cells, miR- 124-3p overexpression reduced cell proliferation and invasion. Cells arrested at the G1 / G0 phase, and the apoptosis rate increased. Suppressing miR-124-3P expression produced opposite result . The dual luciferase reporter experiment showed that MAPK 14 was the target of miR-124-3P. Suppressing the expression of MAPK 14 produced result that were consistent with the miR-124-3Poverexpression effects, i.e., the cell viability and invasion ability decreased, and the apoptosis rate increased. In contrast, MAPK 14 overexpression in the experimental group was consistent with the effects of inhibition of miR-124-3P expression. Conclusions miR-124-3P negatively regulates MAPK 14 and affects the proliferation and invasion of placental trophoblasts in preeclampsia rats.