Abstract: Fitting is used mostly in the transient electromagnetic method inversion at present.However there is a few of deficiencies as following.First, its complex theoretical system is no easy to be mastered;secondly, it is difficult to be popularized in the shortage of inheritance Therefore, scientific researcher is requested to have rich work experience;thirdly, computation complicated for its huge data package.In this paper, an expert system based on artificial neura network is put forward, which avoids detailed and knotted electromagnetic computation.Once afte appropriate training and learning, it can solve practical problem effectively.Furthermore, it memory capacity enhances the continuity and inheritance in the field of TEM inversion.A brigh outlook will be brought along with the consummation of this expert system.