Objective: Wnt-5a is important in the physiological development and differentiation of lung, and is also involved in the regulating proliferation, differentiation and invasion of tumor cells. However, very little is known about the roles of Wnt-5a in the development of lung cancer. The porpus of this study was to explore the role of Wnt-5a in the development of the non-small cell lung cancer, through constructing plasmids containing Wnt-5a sense gene siRNA. Methods: We constructed the plasmids containing the Wnt-5a sense gene and siRNA eukaryotic expression vector and transfected it into the human lung squamous carcinoma cell line H157 and adenocarcinoma cell line A549. Expressions of Wnt-5a RNA and protein and proliferation of the cells were measured. Results: Expression of Wnt-5a protein significantly stimulated cell proliferation, and transfection with siRNA plasmids suppressed Wnt-5 expression and cell proliferation. Conclusion: The human plasmids containing Wnt-5a sense gene and siRNA eukaryotic expression vector was successfully constructed, and transfection to human cancer cells induces cell proliferation. siRNA actively suppressed Wnt-5a expression. © 2009 Elsevier Ltd. All rights reserved.