Abstract: The reflection seismic profile from Dengxian to Nanzhang is the southward extension of the reflection seismic profile from Yexian to Dengxian. The completion of this profile declared the first reflection seismic profile from the Sino? Juan Korean Craton to the Yangtze Craton, across the Qinling Orogen. The Dengxian? Juan the Nanzhang reflection profile clearly shows the fact that the Crust of the Yangtze Craton was subducted beneath the Qinling Orogen and Gives evidence that The Xianyang? Juan Guangji fault (i. e. The North Dabie? Juan Daba frontal fault? Juan fold zone) is not a plate suture, but a continental crustal subducting fault. The crust of the Yangtze craton was subducted beneath the Qinling orogen along the bottom of the upper crust at a depth of about 20km.