Abstract: The velocity data from seismic transformed wave bathymetric profile and seismic tomographic profile are analyzed and shown that Ruoqiang-Altai area possesses continental crust with three layers of velocity structures in south of Bolokenu-Aqikekuduk faulting, composed of upper, middle and lower crustal layers, and in north of the faulting, with two layers of velocity structures composed of middle and lower crustal layers,without marine crust of upper crustal layer. According to distributions, corresponding locations and thickness changes of these velocity layers, the crustal structure in this area can be divided into four types of Tarim, Junggar, Tianshan (superimposed type) and Altai (decoupling type). In-depth description of these four types of crustal structures is made in this paper.

Key words: Xinjiang, Altai, Ruoqiang, Korla, velocity, crust, structure