Abstract: By collecting, translating and studying a large number of research literature on the weathered crust at home and abroad, the authors have reviewed the research status of the weathered crust, and expounded on the research progress of the red clay in southern China in terms of genesis, age, environment and climate. The progress of geological survey about the weathered crust at home and abroad is introduced in this paper in the form examples. And successful examples of special geomorphic areas at home and abroad in geological, geophysical, geochemical, pedological, remote sensing and drilling aspects are emphasized. The research status of the geological survey about the weathered crust is reviewed from both theoretical and practical aspects in order to serve the 1∶50 000 geological mapping and pilot work about the weathered crust in special geomorphic areas.