Abstract: Based on the finite time-domain difference method, the echo signals received by the electromagnetic field penetrating technology are under the typical soil structure(composed of dry soil, moist clay,concrete and asphalt. It is found that the minimum propagation time of the electromagnetic wave in the dry soil is the shortest, and the vertex of the hyperbola is the closest to the horizontal axis. The relative permittivity of the moist clay is the largest, so the vertex(coordinate of the hyperbola is from the horizontal coordinate farthest; the dielectric constants of concrete and asphalt are centered, and the time coordinates of their hyperbolic vertices are in the middle of the two. Based on the finite time domain difference meth od the echo hyperbolic signal system of four typical soil structures is analyzed, which has a good guiding effect on the actual test environment.