In view of severe radiation of ultraviolet radiation B, bad on-site working conditions, easily leading to missed detection of traditional phosphor magnet powder flaw detection methods, the light source of phosphor magnet power flaw detection for tyre surface is optimally designed. A UV-LED light source is adopted as the excitation light source, it achieves matching between the UV-spectrum and the excited spectrum of the phosphor magnet powder. 108 UV-LED lights source arranged in arrays to obtain the high intensity and uniform illumination. The LED lights source with filter glass can filter out harmful ultraviolet rays and useless visible lights. The results show that the designed UV-LED lights source can meet the requirements of phosphor magnet power flaw detection for tyre surface.