From the data of 7 artificial explosions and 10 moderate strong earthquakes of nearby regions recorded by the Shaanxi Seismic Network and also the data of head wave pn from Moho, the time-term bi and vpn for each observation spot and the crustal thickness beneath 40 observation sots are determined by use of the improved time-term method[1] and relative time-term method[3],[4]. Generally speaking, the crustal thickness in Shaanxi region is thinner in the east and thicker in the west. The crust in northern Shaanxi is relatively thick, about 41-43kin. For faulted regions in the Qinling Mountains, it is about 40 kin. The crust in the weihe Basin is relatively thin, about 36 km on ae average. The results suggest that there exist a certain relation between deep crustal structure and seismic activity.