The focal-mechanism solutions of 372 earthquakes in Ningxia and its neighboring regions are evaluated by using Nulff net. Basing on these data the direction of principal compressive stress and principal strain stress in this region are obtained by use Wulff net again. The dominant direction of P axle is NE 30°~70°,and one of T axle is NW 300°~330°. According main acting force is horizontal or nearly horizontal,most of the tectonic faults which causing earthquake should be strike-slip or nearly strike-slip faults.