Abstract：If steep reflection waves in stack time section are interpreted according to the principle of zero-offset reflection waves, their geometric and dynamic characteristics will be distorted, causing misinterpreted geological structure and lithology. Hence, I use the principle of geometric seismology to analyse both the geometric factors resuiting in steep reflection variation and the regular variation of dynamic characteristic parameters of steep reflection waves，such as amplitude，frequency spectrum and S/N ratio. The method is given of how we determine the termination points of reflection waves in stack time section.
