Objective To investigate the effect of knocking down miR-19a on proliferation and apoptosis of human glioma cell line U251 in vitro.Methods U251 cells were cultured routinely.MiR-19a inhibitor was transfected into U251 cells by Lipofectamine 2000.At the same time,the negative control group and blank control group were established.The expression level of miR-19a was detected by RT-PCR.and cell proliferation was analyzed by CCK-8 assay.The changes of cell apoptosis and cycle were monitored by flow cytometry.Results Compared with the negative control group and blank control group,qRT-PCR showed that the expression level of miR-19a was significantly reduced after transfection (F=124.72,P ＜ 0.01).CCK-8 revealed that proliferation ability of miR-19a inhibitor group was significantly suppressed.The cell survival rate in miR-19a inhibitor group after 48 h was (48.27-±8.23) ％,compared with the blank control group (100.00 ％),the difference was statistically significant (t =12.45,P ＜ 0.01).After low-expression of m iR-19a,the G0/G1 phase cells were increased and S phase cells were decreased.The low-expression of miR-19a could induce cell apoptosis.Conclusions Low-expression of miR-19a can inhibit cell proliferation,block G1/S transition and induce apoptosis in human glioma cell line U251.miR-19a may serve as an attractive target of gene therapy for glioblastoma.