BRD7 is a novel bromodomain gene isolated by cDNA representational difference analysis (GenBank accession number: AF152604). Ectopic expression of BRD7 inhibited NPC cell growth and cell cycle progression.Previous studies demonstrated that BRD7 gene could regulate the activity of Rb/E2F pathway. In order to further explore the molecular mechanisms of BRD7 regulating Rb/E2F pathway, Westernblot and RT-PCR analysis were carried out. Results showed that BRD7 could inhibit the phosphorylation of Rb, decrease the expression of cyclin D1 and cyclin E, up-regulate p19 in RNA level, but had no effects on the expression of CDK4 and CDK2. Luciferase reporter assay suggested that BRD7 repressed cyclin D1 promoter activity. Furthermore, an antisense nucleic acids technology was performed to silence the endogenous BRD7 gene in COS7 which resulted in the upregulation of cyclin D1, cyclin E, phosphorylated Rb, and acceleration of the cell growth. As a result of this research, BRD7 inhibits G1-S phase progression in cell cycle via regulating the important molecules involved in Rb/E2F pathway.