Abstract: In the eastern section of the Qinling geotectonic belts, the authors discovered an ancient subduction zone at the northern foot of the Mt. Dabie near Xinyang, Henan province. The subduction complex consists of ophiolites, melanges and low-T/high-P metamorphic rocks. The melanges are composed of native blocks (dolomite-marble, olisto-strome), exotic blocks (serpentinite, issite, hornblendite, granite, gabbro, chert, etc.) and argillo-arenaceous matrix. The suite of ophiolite includes metamorphosed basic volcanic rocks, diabase dykes, metamorphic pelites, basic and ultrabasic magmatic rocks. The essential characteristics of the suite are coincident with those of the island-arc ophiolites. 3T-phengites and C-type eclogites have been found in the low-T/high-P zone of meta-morphism. According to their general tectonic character the subduction complex was produced by a marginal sea floor underthrusting southwards beneath an island-arc. The acorites, sampled from the low-T/high-P zone, have been dated at 693-603 Ma by U-Pb age determination. The quartz-diorites, which intruded into the ophiolitic suite, have been dated at 413.5 Ma by K-Ar age determination. These ages imply that the subduction zone was formed in the end of Late Proterozoic.We suggest that the structural evolution of the ancient convergent plate margins should be divided into following three episodes.(1) During Late Proterozoic (about 700-800 m.y. B.P.), the oceanic crust of the East Qinling Sea underthrusting northwards beneath the continental block of North China, which gave rise to the Tongbai island, is associated with a marginal sea.(2) Nearly in the end of Late Proterozoic (about 700-600m.y. B.P.), a polarity reversal of this subduction zone occurred. The oceanic crust of the marginal sea was consumed beneath the Tongbai island arc, which resulting in the Xinyang subductio ncomplex.(3) During Early paleozoic (about 600-500m.y. B.P.), the oceanic crust of the East Qinling Sea was subducted northwards again beneath the accreted continental margin along a new Benioff zone.