Abstract: In recent years UV-LEDs（Ultra-Violet Light Emitting Diodes） attract great attention and become new focus in both scientific research and industrial investment for its wide application.In this paper,the current status of material growth,defects,cracking,doping and ohmic contact for AlGaN are reviewed.The development history,technology roadmap and current achievements of UV-LED are discussed in detail.Finally,the application and trend of UV-LED in future are presented.