Abstract：In practical seismic exploration, the shape-complex relief surface is often met, but practically acquired data about surface shape and media can be seen as the value at each point of grid after rectangular partition of certain region when carrying out numeric simulation. The acquired surface is step surface that makes a great difference to real surface. Using step surface data for wave equation simulation of seismic data can produce serious interference at corner points of steps and further affect the results of numeric simulation. Using a-coustic equation, the paper conducts spline interpolation for step surface data and results in quadrilateral grid partition coincident with relief surface. The computational results of theoretical models and real data show the computation by using spline interpolation method to approach surface can eliminate the errors produced by the singularity of corner points, reduce the interference and improve the computational precision.
