Abstract:Based on the CINRAD/SA Doppler radar and sounding data, the super-refraction radar echoes, meteorological condition, and atmospheric duct of the two cases that took place respectively on September 5,2006,and November 21,2005 in the north China plain, are compared in this article. The transmission paths of radio in different kinds of atmospheric duct are also analyzed . The results indicate that atmospheric duct transmission of radio can be formed under favorable meteorological condition. Atmospheric duct increases clutter radar echoes, and forms super-refraction radar echoes.The atmospheric duct affects the intensity and distribution of super-refraction echoes. On September 5,2006,there is superficial duct in the atmosphere over Shijiazhuang radar site, and forms 2 level mode super-refraction radar echoes. On November 21,2005, there is raising duct in the atmosphere over radar site, and the super-refraction radar echoes are 3 level mode. The super-refraction radar echoes bring more measuring errors, especially in the height. Super-refraction radar echoes are mainly distributed in the region of east plain because of Taihang Mountain relief.