The utilization of volatile organic compounds and sulfide gases as indices in the exploration of metallic deposits is merely at the preliminary test stage both in China and abroad. In recent years, the authors used hydrogen sulfide dioxide and light hydrocarbon gases (C₁—C₄ paraffin and olefin) as indices to perform the test on the exploration of concealed deposits through soil and surface rock survey within ten lead-zinc, copper-molybdenum, gold and copper-nickel polymetallic deposits in different areas and under different landscape conditions and, as a result, obtained excellent results. It is demonstrated that the method is an effective gasometric technique used in surface soil and rock survey as well as rock body evaluation with the purpose of looking for concealed deposits beneath transported overburden several to more than 400m in thickness and blind deposits over 400m under the bedrock surface. Tests also show that this method is more effective in rock survey than in soil survey.