objective:to observe the radiosensitization effects of human recombinant endostatin(endostar) combined with radiation by establishing subcutaneous transplantation tumor model of nasopharyngeal carcinoma in balb/c nude mice. methods:the nasopharyngeal carcinoma model in balb/c nude mice was established by subcutaneous transplantation of cne1 cell. the diameters of the tumor in the control group(group a), endostar treated group(group b), radiation treated group(group c) and endostar combined with radiation group(group d) were measured every 4 days, the growth curves of tumor were observed, tumor volumes and expected value/observed value(e/o) were calculated. the inhibition rates of tumor by endostar and(or) radiation were calculated according to tumor weight. endostar was injected around tumor 20 mg/kg daily for 10 days, the irradiation dose of local tumor was 20 gy. the expression of hif-1α in tumor was detected by immunohistochemistry staining, apoptosis of tumor cells was observed by transmission electron microscopy. results:in combination with radiotherapy, endostar exhibited significant inhibition of nasopharyngeal carcinoma, the average tumor size of group d[(765.697±78.725)mm3] was significantly lower than group b [(2340.186±370.606)mm3], group c [(1454.028±180.371)mm3] and group a [(3112.452±720.764)mm3] after treated for 4 weeks, tumor weight of group d [(0.523±0.180)g] was lower than group b [(1.294±0.346)g], group c [(0.926 ± 0.233)g] and group a [(1.849±0.596)g,p < 0.05], and the inhibition rate of group d(86.11%) was significantly higher than group c(60.45%) and group b(27.12%). immunohistochemistry staining showed the expression of hif-1α decreased in endostar treated group, transmission electron microscope observed the decreased number of tumor cells and significantly increased apoptosis in group d compared with other groups. conclusion:endostar inhibits the growth of nasopharyngeal carcinoma in nude mice and has radiosensitization effect.