Through detailed analyses for available data concerning low-velocity and high conductive layer beneath the crust and seismic depths, based on the studying of seismic precursors, characteristics and physical mechanisms, a simple double-storey seismogenic hypothesis of the crust for continental strong shocks is preliminarily presented in this paper. The upper layer in mid-upper crust is main earthquake pregnant layer where stress concentrats and strain energy releases in earthquakes events, and is a brittle deformation layer of rocks. The lower one in mid-lower crust with high conductive and low velocity of P wave, is believed that it is one of the most important factors inducing and enhancing brittle deformation, strain energy cumulation and crack in the upper rocks. The latter layer locates in a transitional zone of rock deformation from brittle to ductile, which is closely associated with the occurrence of strong shocks. Meanwhile, seismogenic environment and significance for strong shocks based on the double-storey pattern are discussed in paper.