Objective To compare the differences of five different ultraviolet light （UV） devices in killing Bacillus subtilis and degrading nucleic acids .Methods The Bacillus subtilis suspensions with same concentration were placed 5 cm away from the lamp sources and irradiated by the biosafety cabinet UV lamp， 185 ozone producing ultraviolet lamp， BKS-UV2016 household ultraviolet lamp， JT8-Y30W ultraviolet lamp and deep UVC-LED for 1 min， 30 s， 10 s， and 5 s， respectively. Culture CFUs （Clone Forming Unit） were compared After 24 hours. Bacterial genome and PCR products were placed 5 cm from the lamp sources and irradiated for 1 minute by the five UV devices mentioned above. The PCR results were compared to analyse the template concentration difference. If the device degrade nucleic acids， the irradiation time was reduced to further analyze the device.Results In killing Bacillus subtilis experiment， five UV devices could kill the bacteria after irradiation for 1 minute， but deep UVC-LED had the strongest killing effect when the time was reduced. In bacterial genome and PCR product degradation experiments， only deep UVC-LED showed degradation， and the effect weakens with the decrease of irradiation time and concentration gradually.Conclusion Deep UVC-LED has a stronger killing effect on Bacillus subtilis in short time，and the device can degrade nucleic acids to solve some PCR pollution problems.