Abstract: As Qinling sea basin closed in Indo-chinese epoch and then subducted to inner continent in Yanshan epoch after folding, thrusting and doming-up and the earth crust sharply shortened, strong compression between Qinling and Huabei continental crusts, along with the existence of the nearly west-east oringinal large fault,caused all the South Qinling fault blocks thrusting and obducting toward Yangtze continental crust, and all the North Qinling fault blocks thrusting toward Qinling continental crust along the low velocity zone in the middle earth crust. As a result, two large south - verging thrust systems of piggyback propagation type developed in East Qinling. This paper details their structural features,forming conditions and relationships.