Abstract: Based on studies of tectonic setting, sedimentary environment, spatial distribution and geochemistry parameters of Paleozoic marine mudstone and shale in Yangtze area, the paper suggests that the black mudstone and shale have basic geological conditions for shale-gas occurrence and accumulations, and puts forward two sets of significance exploration stratum, viz Hetang Formation of Lower Cambrian and Longtan Formation of Upper Permian and suggests the favorable exploration area, respectively. The weakness area of tectonics deformation and structural destruction, with great potential of shale gas resource, should be priority of shale gas exploration and development in the lower Yangtze area.