To determine the effect of RAB5A gene over-expression on invasion and differentiation of Human Lung Adnocarcinoma Cells SPC-al and GLC-82. Using constructed antisense RNA of RAB5A (pcDNA3--AntiRAB5A) and RAB5A eukaryotic expression vector (pcDNA3.1-RAB5A), we stably transfected them into low differentiation human lung adenocarcinoma GLC-82 cell and human lung adenocarcinoma cells SPC-al with low metastasis potential capability respectively in vitro. We observed the change of capability of transfected cells in invading recombinant basic membrane and chemotactic motion experiment in vitro, and we make use of hypodermic method with tumor cells in nude to observe the change of differentiation in transfected GLC-82 cells. The transfected GLC-82 cells with pcDNA3--antiRAB5A showed notable alteration. The capability of invading recombinant basic membrane and chemotatic motion decreased in transfected GLC-82 cells. The differentiation of transfected GLC-82 cells was apparently improved. The array of adenocytes is regular and it appears adenoid structure. After RAB5A eukaryotic expression plasmid was transfected into SPC-al, the invasive activity of cells is increased. Over expression of RAB5A played an important role in invasion and differentiation of human lung adenocarcinoma cells SPC-al and GLC-82.