Abstract: The limited power of small energy sparker has confined its wide application on the elastic wave CT in layered medium. This paper introduces the ZDF-3 type high-power sparker as well as its application in cross-hole elastic wave CT, aided by seismic instruments. Two examples of ground-based CT were demonstrated, showing that the cost of large-distance CT detection was lower than the traditional shot-distance CT detection. This study indicates that the application of high- energy sparker of the large cross-hole CT has a good prospect.