Abstract: :The existence of cavern would bring great or potential dangers to every kind of construction engineering. Cross-well seismic computerized tomography(seismic CT) technology is a new geophysics method. This method can efficiently and accurately inverse the inhomogeneous distribution of layers between the wells. This theme is about the principles and methods of cross-well seismic CT technology, and it introduces the application of this technology in a factual cavern survey engineering. In the engineering, the authors combine the result of drilling survey and inversion result of seismic CT technology, and then analyze the two comparative results. As the analysis shows, the seismic CT technology have the advantages of higher precision and credibility, which can make preciser imaging of subsurface medium in engineering geophysics than usual explorative methods.