Abstract: The seismic reflection/refraction profiles are arranged along Qitai-Karamay-Emin, Wucaiwan-Santai-Bogda cross West Junggar mountain, Junggar basin and Bogda mountain, ascertaining 2D crustal velocity, deep crustal structures and crustal layers and acquiring B, G, C₁, C, and M interfaces and velocity structures of P, S wave as well as their velocity ratios. The study shows that the earth crust in this region can be divided into upper crust and lower one. The upper crust includes sediments above the basement faults lying on G, G-C₁, C₁-C interfaces; the lower crust appears between C and M interfaces, there exist deep fault zones such as Dalbute, Karamay, East Daguai, Fukang and northern margin of Bogda as well as 4 steep dipping super-crustal faults in hinterland of Junggar basin. The interface T under the West Junggar orogenic belt is buried in depth of 11.6～12.4 km, and the thrust fault surface at bottom of west-dipping Zhayier nappe structure is recognized. In Bogda mountain area, there is a discontinuous interface between crust and mantle which is sharply deepen toward south from 50.6 km to 69.0 km in depth. In its northern margin, the fault belt is in gentle dipping at the surface and then steep dipping toward the deep, forming the disagreement of orogeny between the surface and the deep.

Key words: Junggar basin, surrounding mountains, seismic exploration, crustal structure, zonation