Shiquan M_L4.9 earthquake on April 24,2003,Shaanxi province,is a typical mainshock-aftershock sequence. The macro epicenter is at Qingnijian, Zhongchixiang,Shiquan County.The meizoseismal region is just on the Liziba-Yingfeng-Tiefosi fault and its long-axis is nearly identical with the fault extended direction. But the attenuation of its biggest velocity of vibration is slower in NS direction than in EW direction, not comforms to the attenuation of intensity isolines.