【Objective】To investigate the effect of miR- 127-3p on proliferation，apoptosis，migration and invasion of uveal melanoma cells.【Methods】The expression of miR- 127- 3p and MAPK4 mRNA in human uveal melanoma tissues and cells，normal tissues and cells were detected by RT-qPCR. The mimic-NC，miR-127-3p mimic，pc-MAPK4 plasmids were transfected into SP6.5 or OM431 cells，respectively，by Lipofectamine 2000. The relationship between miR-127-3p and MAPK4 counterstaining was detected by dual luciferase assay. Cell proliferation was detected by CCK- 8 method，apoptosis was detected by flow cytometry，cell migration ability was detected by scratch test，cell invasion ability was detected by Transwell method，and relative expression level of AKT/mTOR pathway protein was detected by Western blot.【Results】In uveal melanoma tissues and cell lines，the expression of miR- 127-3p was down-regulated（P < 0.01）while that of MAPK4 expression was significantly up-regulated（P < 0.01）. The binding site of miR-127-3p and MAPK4 3′UTR region，the high expression of miR-127-3p significantly inhibited the luciferase activity of wild-type MAPK4 plasmid（P < 0.01），but the mutant MAPK4 plasmid Luciferase activity has no effect. Compared with the Control group ，the proliferation of SP6.5 cells and OM431 cells in miR- 127-3p mimic group were significantly decreased（P < 0.01），and the apoptotic rate was significantly increased（P < 0.01）. The scratch closure rate was obvious. The decrease（P < 0.01）， the number of invading cells per field was significantly decreased（P < 0.01），and the expression of p-AKT（T308）/AKT and p-mTORr（S473）/mTOR protein were significantly down-regulated（P < 0.01）. Transfection of pc-MAPK4 reversed the above changes.【Conclusion】MiR-127-3p inhibits proliferation，migration and invasion of uveal melanoma cells and induces apoptosis by down-regulating MAPK4，which may be involved in the inhibition of AKT/mTOR pathway activation.