“Known for unknown” is an important guiding ideology and prospecting method in mineral exploration and a work based on the known clues for prospecting. “Known for unknown” discuss relative to the prospecting for new working target，mainly in space layout and the difference between the point and the surface and the unknown regions and known ore deposits，and put forward prospecting method to analysis of development theory in “Known for unknown”. And then promote and determine “Known for unknown” theory in ore prospecting work in practical the route.