Valence-varying elements are extensively existent in nature. Elements of different valence states have different geochemical behaviors, which reflect different redox environments. In the ore-forming process, these elements can form their respective characteristic element associations and mineral assemblages. Using E_h-pH graph and geochemical characteristics of some valence-varying elements with different valence states, the authors analyzed mineral stability and coexistence and migration capacity of elements with different valence states so as to extract ore-prospecting information and thus improve the quality of evaluation of ore-prospecting work.