Objective: To investigate the inhibitory effects of PTEN gene transfection combined with L-OHP on human cholangiocarcinoma cell line, QBC939, providing a new method for gene therapy of human biliary duct carcinoma. Methods: A eukaryotic expression vector containing PTEN gene was transfected into human QBC939 cells under mediation of lipofectamine and positive cell clones were selected and amplified. Expression of PTEN gene was detected by immunohistochemistry. MTT test was used to determine the in vitro activity of cells, electron microscope was applied to observe cell ultrastructure, and flow cytometry was used for determining the cell cycle and apoptosis. In vitro test was used to study the invasive ability of cells before and after treatment. Results: After transfected with PTEN gene, QBC939 cells had a higher expression of PTEN gene (P