The Xiaoliang Soil and Water Conservation Station of Guangdong Province is located on the Tropic of Cancer. It is a designated station of Human and Biosphere of the United Nation. Based on the field observation and sampling, this study analyzes the characteristics of mineralogy and magnetic susceptibility of baredground（ecosystem being destroyed）profile and ecosystemresumed profile, and the implications in the succession of ecologic environments. It is demonstrated that the magnetic susceptibility differs in two granite weathering crust profiles located under different ecosystems, as controlled by different magnetic minerals. Low values of low frequency magnetic susceptibility and its faint correlation with water content are characteristics of the baredground profile. The dominant magnetic minerals in the profile are evidenced to be hematite and goethite by power XRD. By contrast, low frequency magnetic susceptibility is much higher in the ecosystemresumed profile and shows a good correlation with the water content. Magnetite and maghemite is pronounced to be the dominant magnetic minerals by power XRD.The frequency magnetic susceptibility descends  with the depth of the profile,which  shows a diversification trend of the concentration of superparamagnetic minerals and reflects the effect and alteration of granite weathering crust by biotic factors. There is a definite relation between the characteristics of magnetic susceptibility of the granite weathering crust and the succession of ecologic environments.