Abstract: A systematic measurement on the soil mercury gas, thermal released mercury and the total mercury was developed in the copper mine of Chengmenshan. The results showed that there were obviously enrichment of soil mercury gas and thermal released mercury in the soil above the granodiorite porphyry and fracture zones. The main source of the soil mercury gas is the deep sulfide ore-body, and the anomaly of mercury gas correctly reflects the hosting location of the ore-body. The total mercury in soil can not give the exact information as there is also background mercury. By the ratio of total mercury and thermal released mercury in soil we can dilute the background mercury, thus it shall highlight the thermal releases mercury, and return information of deep mineralization more clearly. So it is a useful geochemistry index which can indicate the deep mineralization.