In this paper, based on the geophysical field,the magnetic sounding formula and more general one of gravity sounding are submitted by way of the derivation of mathematics and physics in geo-physical circle. In order to receive more exact solution,the iterative inversion in space domain is put forward with optimization theory. On the other hand,in light of geophysical model,we improve the Gauss optimization theory so that the calculating method is simple and the computing soeed is very quick.With an amount of test results of various models listed in this paper,the effectivity and reliabili-ty of the magnetic sounding formula are also discussed.It is satisfaction to process the practical data using the method proposed in this paper,and its practical value has been testified.