The　roles　of　microRNAs　(miRNAs)　in　liver　cancer　have　attracted　much　attention　in　recent　years.　In　this　study,　we　demonstrate　that　miR-520b　is　downregulated　in　MHCC-97H　cells,　a　liver　cancer　cell　line　with　high　potential　of　metastasis,　compared　with　MHCC-97L　cells　which　has　a　low　potential　of　metastasis.　Furthermore,　the　enhanced　expression　of　miR-520b　could　inhibit　liver　cancer　cell　migration,　while　silencing　its　expression　resulted　in　increased　migration.　Mixed　lineage　kinase　3　(MLK3)　was　identified　as　a　direct　and　functional　new　target　of　miR-520b.　This　regulation　was　also　confirmed　by　luciferase　reporter　assays.　In　addition,　our　results　showed　that　overexpression　of　the　MLK3　expression　partially　reversed　the　effect　of　miR-520b　on　liver　cancer　cell　migration,　indicating　that　MLK3　contributes　to　the　migration　in　liver　cancer.　The　newly　identified　miR-520b/MLK3　axis　partially　elucidates　the　molecular　mechanism　of　liver　cancer　cell　migration　and　represents　a　new　potential　therapeutic　target　for　liver　cancer　treatment.