The characteristics of elevated duct over south central region of western Pacific from November 2015 to January 2016 was analyzed by ship-based GPS sounding and ECMWF reanalysis data (ERA-Interim). The results showed that the occurrence probability of elevated duct was 47%. The mean height, thickness, and magnitude were 1 393 m, 205 m, and 11.7 M-unit, respectively. When elevated duct occurred, the weather was fine with little cumulus. The occurrence probability of elevated duct in 5—30°N region was up to 77%, intense elevated duct existed at about 800 hPa. ERA-Interim reanalysis data indicated that the intense elevated duct occurred in huge anticyclones. Strong relative humidity gradient and temperature inversion, which make for the intense elevated duct, was caused by encounter of slowly sinking dry air inside the subtropical anticyclone with the wet ascending marine boundary air.