Objective： To investigate the inhibitory effect and IC50（50% inhibiting concentration） of the recombinant adenoviral p53 gene （rAdp53） in colorectal cancer cells in vitro and to guide clinical practice. Methods： We evaluated the efficiency（IC50）of the rAdp53 and six kinds of anti-cancer drugs（5-fluorouracil, tegafur, mitomycin c, cisplatin, oxaliplatin, paclitaxel） in human colorectal cancer cell line-174 through the cell culture and MTT chemosensitivity assay to make sure the anti-cancer capability of rAdp53. Expression of p53 protein in transfection cells of colorectal cancer line-174 with rAdp53 was evaluated by immunohistochemical staining. Results： The rAdp53 is a dose- and time-dependent anti-cancer drug, its IC50 is 5.73×1011 VP/ml, but its effect was not obvious when compared with other anti-cancer drugs. In control group, the immunohistochemistry stain was negative. However, rAd-p53 of five different concentrations were all positive in infected colorectal cancer cells with rAd-p53 and the earliest positive result would present 24 hours after infection. Conclusion： The rAdp53 has good anti-cancer efficacy is colorectal cancer cell line-174 in vitro. But its anti-cancer efficacy was less than those of the classical chemical medicine mitomycin c, 5-fluorouracil and cisplatin etc., when it was used alone.