Abstract: The porphyry type molybdenum ore belt in east Qinling measures more than 200km long and 20km wide, forming a NWW-trending rectangle. Mineralizations are equidistantly distributed along NE direction like a string of beads. It is a typical crossed area of the geochemical steep-dipping zone and geo physical gradient zone. Along a plunging mantle syncline in E-W plunging direction and from the east to the west are distributed check-shaped fractures which control the synergic crust-mantle grano-porphyry rocks in the Luonan-luanchuan area. Our preliminary interpretation is as follows: The Luonan-Luan chuan area at depth wan a westward plunging mantle syncline with a nearly E-W axis direction. The geochemical boundary was controlled by the strike direction of syncline. The geophysical gradient zone was controlled by the steep slope of the syncline. The crossing effect caused the structural fracture assembly on the NNE direction a long the rigid block margin. These superimposed upon parallel fracture bunches on the ancient continental margin, which were expressed as the check-shaped distribution pattern. Under the influence of crust-mantle interaction the fluid moved up along the structures to the shallower crust and form ed mineral deposits There occurs a series of small masses of early and late Yanshanian granite porphyries, diorite and various dyke rocks of acid-intermediate compositions The main controlling factors of this porphyry molybdenum ore halt were dependent on the character of magmatic activities and conditions of occurrences. The molybdenum mineralization was closely related to the highly acidic, alkali and potash-rich Yanshanian small intrusive bodies. Both the rock-forming and ore-forming processes are structurally controlled in time and space.