The method using arrival-time difference between sPn and Pn phase of seismic wave to determine the depth of seismic resource in near region within crust is simple and accurate. In this paper, the sPn phase of Dongwuzhumuqin MS. 9 earthquake on March 24,2004, recorded by different seismic stations their epicentral distances are no more than 1 000 km in Inner Mongolia Autonomous Region are primary analyzed, and the depth of event focal is calculated. Meanwhile the possibility that using sPn phase to determine depth of seismic resource and application of this method to daily earthquake monitoring work are discussed.