In order to identify and analyze superrefraction echoes accurately, a nd take great advantage of the Doppler radar， based on the Doppler radar data in Shijiazhuang and the sounding data, the ray path of the superrefraction radar echoes in the dense fog weather occurring in North China Plain during 19-21 Nove mber, 2005 is studied. The results indicate that, the dense fog weather is favor able for the occurrence of atmospheric duct and the formation of 3 layer mode su perrefraction echoes. The superrefraction radar echoes bring about measuring err ors, especially in the height. The superrefraction radar echoes occur when the f og develops or maintains. These present the new means and lay the scientific bas is for the spatial location by radar， and the monitoring and forecast of dense fog weather in North China Plain.