〔Abstract〕 Objective To investigate the effects of Pizotifen on proliferation, migration and invasion of A549 and PC9 cells of human lung adenocarcinoma and its possible mechanisms. Methods The logarithmic phase of A549 and PC9 cells were used for experiments, which were divided into control groups(cell control group and DMSO solvent control group) and experimental groups(including 10,20,30 and 40 μmol/L Pizotifen, respectively).CCK-8 assay was used to evaluate the effects of Pizotifen on A549 and PC9 cells proliferation. Wound-healing assay andTranswell assay were then performed to investigate whether Pizotifen affected the migration and invasion properties of A549 and PC9 cells. Finally, ELISA was used to determine the expression levels of Wnt3a/β-catenin signaling pathway related proteins and epithelial-mesenchymal transition(EMT) related proteins such as E-cadherin(E-cad) and matrix metalloproteinase-9(MMP-9) in A549 and PC9 cells after Pizotifen treatment. Results Compared with the solvent control group, the assay of CCK-8 in experimental groups showed that the cell vitality gradually decreased after Pizotifen treatment for 24 h and 48 h, and the inhibition rate of cell vitality was directly proportional to the action time of Pizotifen(P<0.05). At the same treatment time, the cell viability of A549 and PC9 in the experimental groups decreased with the increase of Pizotifen concentrations(20, 30 and 40 μmol/L).The test of Wound-healing showed that Pizotifen had an inhibitory effect on the migration of A549 and PC9 cells, and the higher the concentration of Pizotifen was, the lower the cell migration rate was(P<0.05). The experiment of Transwell showed that Pizotifen had an inhibitory effect on the migration and invasion of A549 and PC9 cells in a concentration-dependent manner(P<0.05). ELISA showed a decrease in the level of Wnt3a, β-catenin and MMP-9 protein and an increase in E-cad protein in the experimental groups compared with the solvent control group. Conclusion Pizotifen may inhibit the proliferation, migration and invasion of human lung adenocarcinoma A549 and PC9 cells in vitro, with the inhibition strength dependent of the concentration and action time of Pizotifen. Its potential mechanisms may include block of the Wnt3a/β-catenin-EMT pathway in cells.