Abstract: The Dachang tin deposit is a superlarge tin polymetallic ore deposit. The research results of tar, components of inclusions and ores show that there were many organic matters which took part in the process of mineralization, with hydrocarbon being the most important associated components. An analysis of the hydrocarbon content in soil reveals that the background and anomaly of hydrocarbon change obviously, and the authors infer that as there probably existed large amounts of ore-forming liquid, the potential of prospecting for ore deposits in the depth is fairly great. According to the distribution characteristics of hydrocarbon and As, Sb anomalies in combination with geological and structural features, three valuable ore-prospecting target areas were delineated in the region.