Abstract: In allusion to the case that dielectric constant and magnetic permeability vary with the depth of rock stratum, this paper presents the horizontal or vertical spatial distribution feature and corresponding variation law of electromagnetic field of a horizontal magnetic-dipole source. Taking advantage of the algorithm of Hankel J₀ transform linear filters (241 points) and Hankel J₁ transform linear filters (241 points) suggested by Kong, we discuss the spatial distribution characteristic of a horizontal magnetic-dipole source as media dielectric constant and magnetic permeability make changes in the homogeneous earth and two layers geoelectric structure. The result indicates a negative correlation between the amplitude of magnetic field component H_x and magnetic permeability, while a positive correlation between H_z (E_y) and magnetic permeability; meanwhile, the change of dielectric constant scarcely affects magnetic field in the low frequency electromagnetic sounding.