Objective To investigate the effect of ursolic acid on apoptosis and migration of lung cancer A549 cells by regulating miR-373-3p. Methods We used an MTT assay to detect the toxic effects of ursolic acid on A549 lung cancer cells. AnnexinⅤ-FITC/ PI double staining and flow cytometry were used to detect the effect of ursolic acid on A549 cells transfected with miR-373-3p. Real-time fluorescence quantitative PCR was used to detect the expression level of miR- 373-3p in A549 cells in the ursolic acid dosing group and the transfected miR-373-3p mimics group. RT-PCR and Western blot were used to detect mRNA and the protein expression of the downstream target gene, TXNIP, which is regulated by miR-373-3p under the action of ursolic acid. The scratch text was used to evaluate miR-373-3p cell migration ability. Results Ursolic acid significantly decreased the growth viability of A549 lung cancer cells (P<0. 05), with an IC50 of 60 μmol / L. Transiently transfected miR-373-3p mimics up-regulated the expression of miR-373-3p in A549 cells ( 24 h, 11. 367± 2. 120; 48 h, 12. 167 ± 1. 108), and ursolic acid significantly increased the expression level of miR-373-3p mimics in A549 cells transfected with miR-373-3p mimics (24 h, 16. 787±3. 109; 48 h, 16. 980±3. 106). mRNA for the target gene, TXNIP, (10. 757± 0. 79) and protein expression ( 0. 8210± 0. 043) predicted by miR-373-3p mimics were significantly increased. FCM result showed that miR-373-3p promoted apoptosis of A549 lung cancer cells ( 46. 20 ± 5. 970), and after being transfected with miR-373-3p mimics, the cells’ migration ability was significantly inhibited (P< 0. 001). Conclusions Ursolic acid can promote the apoptosis of A549 lung cancer cells and inhibit their migration. The mechanism may involve up-regulation of miR-373-3p expression.