OBJECTIVE To explore the effects of isorhamnetin on the development of gastric cancer through up-regulation of solute carrier family 25 member 25 antisense RNA 1（SLC25A25-AS1）. METHODS Using BALB/c nude mice as the subjects， the xenograft tumor model was established by subcutaneously inoculating human gastric cancer MKN28 cells into the axillary region. The effects of low and high doses of isorhamnetin （20 and 40 mg/kg） on the tumor volume and mass in nude mice were investigated. MKN28 cells were selected and divided into control group， isorhamnetin group （70 μmol/L， similarly hereinafter）， isorhamnetin+knocking down negative control group， isorhamnetin+knocking down SLC25A25-AS1 group， isorhamnetin+ overexpression negative control group and isorhamnetin+overexpressing SLC25A25-AS1 group. Effects of knocking down/ overexpressing SLC25A25-AS1 on viability， apoptosis， migration and invasion ability of isorhamnetin-treated cells were detected. After verifying the targeting relationships between microRNA-212-3p （miR-212-3p） and SLC25A25-AS1， as well as phosphatase and tensin homologue deleted on chromosome 10 （PTEN）， the effects of knocking down/overexpressing SLC25A25-AS1 on the expression of miR-212-3p， PTEN mRNA， and PTEN protein in isorhamnetin-treated cells were investigated. RESULTS Compared with the model control group， tumor volume and mass of nude mice in the isorhamnetin low-dose and high-dose groups were reduced significantly， and the isorhamnetin high-dose group was significantly lower than the isorhamnetin low-dose group （P＜0.05）. miR-212-3p had targeting relationships with SLC25A25-AS1 and PTEN. Compared with the control group， the cell viability （intervened for 24， 48 h）， migration number， invasion number and miR-212-3p expression of cells in the isorhamnetin group， isorhamnetin+knocking down negative control group and isorhamnetin+overexpressing negative control group were significantly reduced or decreased or down-regulated， while the apoptosis rate， mRNA and protein expressions of PTEN were significantly increased or up-regulated （P＜0.05）. Compared with isorhamnetin group and isorhamnetin+knocking down negative control group， the cell viability， migration number， invasion number and miR-212-3p expression of cells in the isorhamnetin+knocking down SLC25A25-AS1 group were significantly increased or up- regulated， while the apoptosis rate， mRNA and protein expressions of PTEN were significantly reduced or down-regulated （P＜ 0.05）. Compared with isorhamnetin group and isorhamnetin+overexpressing negative control group， the cell viability， migration number， invasion number and miR-212-3p expression of cells in isorhamnetin+overexpressing SLC25A25-AS1 group were significantly reduced or decreased or down-regulated， while the apoptosis rate， PTEN mRNA and protein expressions were significantly increased or up-regulated （P＜0.05）. CONCLUSIONS Isorhamnetin may inhibit the development of gastric cancer by up-regulating the expression of SLC25A25-AS1， down-regulating miR-212-3p， and up-regulating the expression of PTEN， which is a downstream target of miR-212-3p.