Abstract: The red clay and secondary red clay distributes widely in Kunming city which is in the mid-northern of Yunnan province, with the characteristics of large porosity ratio, low density, high content of clay particle, high plastic limit and liquid limit and larger plasticity index. Moreover, due to its apparent swell-shrink characteristics, the fissures are often formed on the ground surface so that the entirety of the soil body has been broken, as well as the strength and impermeability of the soil body have been degraded, which result in bad influences to the engineering. Therefore, in this paper, based on abundant data of the physical and mechanical experimentations, the distributed chart of the red clay in Kunming city has been drawn by Mapgis software, with the discussion of its distributed characteristic, physical and mechanical properties and swell-shrink characteristics, and then the problems of the fissures and cave in the red clay have been studied.