Cell migration and invasion are triggered by a number of chemoattractants that stimulate intracellular signaling pathways through regulating reorganization of the actin cytoskeleton. Rac1, an intracellular signal transducer, regulates a variety of cell functions, including the organization of the cytoskeleton, cell migration, and invasion. However, currently, very little is known about the roles of Rac1 in the cytoskeleton formation and invasion of human colorectal cancer cells. In our study, Rac1-shRNA was used to silence the Rac1 to reduce its expression specifically in Lovo cells. Our studies showed that RNA interference-mediated deletion of Rac1 strongly inhibited lamellipodia formation, cell migration, and invasion of Lovo cells in vitro. The deletion of Rac1 can serve as an alterative therapy to inhibit the invasion and metastasis of colorectal cancer cells.