Abstract: In this paper, 1-D and 2-D ray tracing traveltime fitting and calculation of synthetic seismograms are performed from DSS data on Wen'an -Yuxian -Qaharyouyizhongqi profile. The velocity structure and tectonics of the crust and upper manttle is determined. The result shows that velocity structure of the crust and upper mantle is obviously inhomgeneous in vertical and lateral directions-M-discontinuity undulates sharply, from a depth of 31km near Baxian in Jizhong depression westward to around 42km at Tianzhen in the north of Shanxi uplift. Shallow faults develop, and deep crustal faults are infered accord ing to the undu1ation of the corresponding deep crustal interfaces, velocity contours and wave group characteristics near the foult zone.