Background Osteosarcoma (OS) is one of common malignant cancers in the world posing high morbidity and mortality. It has previously been demonstrated that microRNAs (miRNAs) hold important functions in the progression of cancers. The purpose of this exploration was to confirm the biological effects of miR-10b on OS. Materials and methods Accessing to the Gene Expression Omnibus (GEO) database, we achieved expressional profiles of miR-10b and FAM46C in OS patients. Kaplan-Meier method was used to predict the overall survival of OS patients. Cells were treated with miR-10b mimic/inhibitor to regulate miR-10b expression. Overexpression of FAM46C was induced by pcDNA3.1-FAM46C. Quantitative real-time PCR (qRT-PCR) and western blot were carried out to assess the expression of miR-10b and FAM46C. Cell counting kit-8 (CCK-8) and transwell assays were employed to evaluate the proliferative, invasive and migratory properties of OS cells. Dual-luciferase reporter assay was applied to determine the target of miR-10b. Results An inverse connection was observed between the overall survival of OS patients and miR-10b expression. MiR-10b was significantly upregulated in OS tissues and cell lines in comparison with normal tissues and cells. Depletion of miR-10b attenuated the proliferation, invasion and migration of MG-63 cells. In addition, FAM46C was considered as a target gene of miR-10b and there was a significant relationship between miR-10b and FAM46C. FAM46C was capable to reverse the functions caused by miR-10b inhibitor in cell vitality of OS cells. Conclusion Down-regulated miR-10b proposed a negative effect on the cell activity in OS cells, providing a novel light into the occurrence and development induced by miR-10b/FAM46C.