Airborne dual-frequency LiDAR detection technology collects simultaneous land and water-depth measurements using dual-wavelength laser. Since 1969, some commercial products have been formed for ocean, coastal zone and reef detection. Since 1998, Shanghai Institute of Optics and Fine Mechanics has successively developed three generations of airborne dual-frequency LiDAR, transforming from principle sample machines to product sample machines. The 11 flights tests of latest Mapper5000 system have been completed in the area of the South China Sea. Topographic and hydrographic data of islands and reefs have been collected. The measured hydrographic range is from 0.25 m to 51 m. The measured hydrographic vertical and horizontal accuracy are 0.23 m and 0.26 m, respectively. The measured hydrographic and topographic spatial density are 1.1 m×1.1 m and 0.25 m×0.25 m, respectively.