Geophysical investigation .was performed along eight magnetotelluric sounding profiles in the Middle-Lower Yangtze Valley and, as a result, fairly systematic data on deep geological structure -were obtained. On such a basis, the authors have advanced new ideas on some important faults and tectonic divisions and, from the plate viewpoint, made a prelimi-nary discussion on such problems as matching of plates, suture lines and oceanic crust subduction. In addition, opinions are raised regarding regional metallogenic prognosis with some new ore prospect areas pointed out.