ObjectiveTo observe the effect of ultraviolet (UV) radiation on the proliferation of acute promyelocytic leukemia (APL) cell line HL-60, and to investigate the appropriate irradiation method and exposure dose of UV. MethodsHL-60 cells were taken as the study objects, control group and UV group were set up, the UV group exposure to 2mJoules (mJ), 6mJ, 10mJ and 15mJ of UV, the wavelength of UV was 254nm, and the control group did not receive UV. The proliferation of HL-60 cells was observed by phase-contrast microscopy, and the cell mortality rate of HL-60 cells was detected by trypan blue staining. ResultsNo significant apoptosis of HL-60 cells was found in the control group; some apoptosis cells were found and the proliferation of HL-60 cells was inhibited while received 2-10 mJ UV for once time; must cells were lysed or completely die while irradiated by 15mJ UV once time or 2-10mJ UV twice time (once every 5 days); after exposured to 10mJ UV, dead cells was found in the first day, and the mortality rate reach the highest value on the third day after irradiation, which had statistically significant differences in comparison with the other groups (P＜0.05),and the mortality rate decreased a long with culture. ConclusionsUV radiation has a significant killing effect on HL-60 cells, as compared with high doses of UV irradiation, repeated exposure to UV of lower doses can also induced apoptosis of HL-60 cells.