Objective To investigate the effects of knocking down long non-coding RNA (lncRNA) BAIAP2 anti‐ sense RNA 1(BAIAP2-AS1) on proliferation, migration and apoptosis of glioma cells and their mechanism. Methods Glioma cell lines A172, LN229, U251 and normal human astrocyte line NHA were cultured in vitro. The mRNA expres‐ sion of microRNA-491-5p (miR-491-5p), BAIAP2-AS1 and O6 -methylguanine-DNA methyltransferase (MGMT) in each cell was detected by RT-qPCR. Glioma cells with significant mRNA expression changes of lncRNA BAIAP2-AS1, miR491-5p and MGMT were selected for follow-up experiments. These glioma cells were randomly divided into the blank con‐ trol group, BAIAP2-AS1 shRNA group, NC shRNA group, BAIAP2-AS1 shRNA+miR-491-5p inhibitor group and BAIAP2-AS1 shRNA+NC inhibitor group, respectively. Cells in the BAIAP2-AS1 shRNA group and NC shRNA group were transfected with BAIAP2-AS1 shRNA and NC shRNA, respectively; cells in the BAIAP2-AS1 shRNA+miR-491-5p inhibitor group and BAIAP2-AS1 shRNA+NC inhibitor group were transfected with BAIAP2-AS1 shRNA and miR-491-5p inhibitor, BAIAP2-AS1 shRNA and NC inhibitor, respectively; cells in the blank control group were not transfected. Af‐ ter transfection for 48 h, cells were collected, and cell activity was detected by MTT assay, apoptosis rate was detected by flow cytometry, cell mobility was detected by cell scratch assay, and mRNA expression levels of BAIAP2-AS1, miR-491- 5p and MGMT were detected by RT-qPCR. StarBase online database was used to predict the complementary sites of miR491-5p, BAIAP2-AS1 and MGMT, and double luciferase reporter gene assay was used to verify the targeted regulatory rela‐ tionship. Results Compared with NHA cells, the relative expression levels of lncRNA BAIAP2-AS1 and MGMT mRNA were higher in A172, LN229 and U251 cells, while the relative expression level of miR-491-5p was lower (all P<0. 05). The relative expression levels of lncRNA BAIAP2-AS1 and MGMT mRNA were higher in U251 cells, while the relative ex‐ pression levels of miR-491-5p were lower, so U251 cells were used for follow-up experiments. Compared with the blank group and NC shRNA group, the cell activity, mobility, expression levels of BAIAP2-AS1, MGMT in the BAIAP2-AS1 shRNA group significantly decreased, and the apoptosis rate, miR-491-5p expression increased (all P<0. 05). Compared with the BAIAP2-AS1 shRNA group and BAIAP2-AS1 shRNA+inhibitor NC group, the cell activity, mobility, MGMT ex‐ pression increased and the apoptosis rate, miR-491-5p expression significantly decreased (all P<0. 05). It was predicted by StarBase online database and verified by double luciferase reporter gene experiment that BAIAP2-AS1 could target and regulate miR-491-5p, and miR-491-5p could target and regulate MGMT. Conclusion Knocking down BAIAP2-AS1 can inhibit proliferation, migration and promote apoptosis of brain glioma cells by regulating miR-491-5p/MGMT axis. [ABSTRACT FROM AUTHOR]