New detection technology of Ordovician limestone water rich property and high accuracy 3D seismic exploration in petroleum geology adopted by coal exploration in widespread mined-out area were discussed systematically in this paper. And a series of accurate key technique measures reflecting technological difficulties were elaborated as well, including collection, processing and interpretation of geophysical exploration technology, advantage of seismic acquisition observation system, key processing techniques and explaining technology of a series of seismic data, making analysis and summary, as well as putting forward understanding and advice.