Abstract: To study the deep structures of basement and crust in Junggar basin, 4seismic profiles from deep-sounding by converted waves of earthquakes have been done with total length of 1600km. The results of investigation show that the crust in Junggar basin features continental character, and the basement of the basin is characterized by two-layer structure, the upper layer is Hercynian folded basement, and the lower is Pre-Cambrian crystalline basement. The total thickness of Hercynian forded basement is less than 10km, to the north of Sangequan swell its thickness is about 3~10km, to the south of it its thickness is only about 0~4km. The depth of the top of Pre-Cambrian crystalline basement is about 5~16km. The total thickness of the crust in the basin changes in range of 44~52km, averages 47~48km. A series of deep fractures have been detected in the basement and the crust in the basin, which are significant in the control of the distribution of oil and gas resources.

Key words: Junggar basin, basement structure, crust structure, deep-sounding by converted waves of earthquakes, deep fracture