Based on great quantity of Pb-Sr-Nd isotopic data from various mantle and crust –derived rocks and ores in Continental China, and global comparison of isotopic and element systematics, the indexes and mapping methods of isotopic geochemistry for the division of geochemical provinces are proposed. The major geochemical provinces in Continental China and their geochemical steep zones, i.e. boundaries, have been established through large scale mapping of Pb isotopic vectors. The generation of geochemical boundaries was tightly related to inclined combination of plates, as well as cratonization resulted in adjustment of lithosphere structure after plate collision. The division of geochemical provinces and establishment of their boundaries not only provide important basis for the paleo-continent reconstruction and ascertaining plate boundaries, but also can be widely applied to exploration and evaluation of resources, establishment of environment background and pollution sources. It is indicated from our study that the giant Au, Cu, Mo, Sn, Ag, Ni, Pb-Zn, U, K salt, B, Mg and P deposits of about 90%, and more than 10 large concentrated mineralization districts in Continental China was controlled by the geochemical steep zones. The geochemical boundaries also controlled the sites of oil-gas fields at the craton margins. As background values of Pb isotopes within a geochemical province is quite stable, based on the background values established by geochemical mapping, fast quantitative evaluation for Pb pollution level can be made.