ObjectiveTo investigate the effect of repeated transfer of liposome mediated CD gene plus radiation on the growth of human rectal cancer cells xenograft in nude mouse Methods HR 8348 cells transfered with liposome mediated CD gene repeatedly (at day 0,4,8,12 ) and treated with fractionated radiation at a dosage of 2 Gy/day to a total dose of 30 Gy. At the same time, mice were injected i.p.with 800 mg/kg/day of 5 FC for 12 days. Results Compared with controls tumors in treatment group grew with an inhibition rate of 78 7% in weight, and 81 5% in volume. ConclusionRepeated transfer of liposome mediated CD gene working together with radiation effect a significant inhibition on the growth of xenografted human rectal carcinoma HR 8348 cells in nude mouse.