Since its discovery, the retinoblastoma (RB) tumor-suppressor protein has become a focal point of caner and cell cycle research, and subsequently discovered members(pRB,p107,p103) of the RBfamily have been proved to play a important role in the cell cycle and the development of cancer. RB regulates the cell growth, development and differentiation via the interactions with E2f and some other cytokines,and its alternation even make the tumor formation. In comparison with some other tumors, colorectal cancer(CRC) has the different expression of RB.We may assume that the different causes of CRC and some unique functions of RB in CRC lead to the alternation.