Abstract: Objective To investigate the effects of KIF4A gene silencing on the proliferation and cell cycle of colorectal cancer cells and related mechanism. Methods KIF4A-CtrlRNA (si-Ctrl) and KIF4A-siRNA (si-KIF4A) were transiently transfected into colorectal cancer cell lines SW480 and DLD1. Western blot was used to determine the effect of gene silencing. The proliferation of SW480 and DLD1 cells were detected by CCK8 assay. Flow cytometry was performed to analyze the effect of KIF4A on cell cycle. The levels of cell cycle-related proteins Cyclin D1, Cyclin E2 and CDK2 were performed by Western blot. Results Compared with the si-Ctrl group, the si-KIF4A group presented significantly reduced proliferation abilities and the levels of Cyclin D1, Cyclin E2 and CDK2, and the cell cycle was arrested at G0/G1 phase. Conclusions KIF4A promotes colorectal cancer cell proliferation through up-regulating the expression of Cyclin D1, Cyclin E2 and CDK2.