On the basis of former seismic and geology data in that area, this paper, beginning from the velocity research, discusses the establishment of fine varied velocity field by studying a lot of seismic velocity spectrum data with smooth and average method. 本文根据该区以往的地震、地质资料,从地震速度研究着手,通过对大量地震速度谱分析,用平滑平均速度的方法建立了精细的三维变速场。