Because of its intuition and convenience, visualization technology is generally applied in geophysics. However, there exist certain limitations in inversing surface or borehole magnetic data alone, which may easily cause multiplicity. In this paper, the authors demonstrated the principle and crucial technology of 3D manmachine interactive inversion of surface and borehole magnetic data, and applied it to the Daye iron mine. This method not only has the full advantage of the surface and borehole magnetic data but also possesses the experience gained by interpretation workers. At the same time, it overcomes the disadvantages of inversing either of them alone and can get favorable result in mineral exploration.