In the current study, we have found that miR-221 level in glioma is significantly higher than that in non-glioma tissues or cells; that miR-221 participates in glioma cell proliferation, migration and invasion; that miR-221 plays its biological roles via negatively regulating the SEMA3B gene in glioma. The gene discussed is SEMA3B; the disease is central nervous system cancer.