Abstract：Ray-tracing not only is one of effective measure for studying the problem of seismic wave propagation,but also plays an important role in seismic tomography and pre-stack depth migration. Its computing precision and speed directly effect on results of tomography and pre-stack depth migration. Changing model-building for-mina in traditional layered earth model,the paper presented a blocky structural model-building method for ray-tracing. New model-building technique can apply ray-tracing to rather complicated geologic objects. C++ language plays an important role in programming of blocky structural model-building method. Real tom-puting case using blocky structure for model-building in rather complicated geologic structure and conducting ray-tracing by iteration is given in the paper.
