Abstract: This paper elucidates the control of heavy metal activity by minerals in soils by using the environmental mineralogy theory and method and analyzes the possible positions of occurrence of heavy metals on mineral surface and in interlayer domains and pore throats in more detail. Experimental study shows that the adsorption of heavy metals by minerals is influenced by factors such as pH values and ion strength of media. The contents of trace,poisonous and harmful heavy metallic elements in stable bound-state sulfide in soils can be calculated by systematic cluster analysis. The mineral composition and contents in soils can be quantitatively determined by X-ray powder diffraction analysis. An evaluation process of soil environmental quality by the mineralogical method is put forward. This method is used to determine the composition and contents of minerals in soils in units and sections,ascertain the composition and distribution of minerals in surface soils and deep soils and evaluate the modes of occurrence of heavy metals in soils and their influence on the food chain. This study aims to provide a new method for evaluation of the agro-geological environment and earnestly improve the quality and service level of agro-geological environmental survey.