The transient electromagnetic method is an effective exploration method for the coalfield mined-out area. The pseudo-seismic processing and interpreting of TEM have gradually become a hot research spot of EM exploration and made some breakthroughs. In this study. The authors employed the pseudo-seismic processing and interpreting method in coal mine goaf detection for higher detecting accuracy. With 3D finite difference time domain method of TEM, a model with two water bearing gobs was simulated. Pre-condition regularized conjugate gradient algorithm was used to realize stable transform from the diffusion field to the virtual wave field. And pulse compression was applied to virtual wave field. Finally, three-dimensional interpretation of the model was realized through the Kirchhoff integral equation downward migration imaging of the fictitious wave field data.