Objective The present study aimed to investigate the effect of CD166 on the radiosensitivity of nasopharyngeal carcinoma cell line CNE-2. Methods CD166 expression in the CNE-2 cell membrane was detected by flow cytometry. CNE-2-CD166（+） and CNE-2-CD166（-） cell lines were obtained using magnetic-activated cell sorting technology. Radiosensitivity，cell proliferation，and apoptosis were assessed，respectively，using a colony formation assay，cell counting kit-8 assay and flow cytometry. Results The CD166（+） rate in the CNE-2 cell membrane was（24.27±5.31）%；after immunomagnetic separation，the CD166（+） rate was 96.5% among CNE2-CD166（+） cells and 0.6% among CNE2-CD166（-） cells. The radiation sensitivity ratio was 1.24. After 10-Gy irradiation，The CCK-8 assay indicated that the survival fraction of CNE-2-CD166（+） cells was （76.66±3.36）% in 24 h，（62.44±1.66）% in 48 h and （55.21±3.39）%in 72 h，significantly higher than that of CNE-2-CD166（-） cells:（60.34±5.13）% in 24 h、（41.11±3.00）% in 48 h，（35.28±4.36）% in 72 h（P＜0.05）. After 10-Gy irradiation，the apoptotic rate of CNE-2-CD166（+） cells was significantly lower than that of CNE-2-CD166（-）cells（P=0.026）. Conclusion Our data suggest that CD166（+） nasopharyngeal carcinoma CNE-2 cells are more resistant to radiation，and the mechanism may be associated with reduced apoptosis rate after irradiation.