Everyone knows heavy metals are inorganic pollutants with strong toxicity and typical pollutant needing preferentially control. In the metal mines of China, the tails that were piled up on the ground already have reached more than 4 billion tons, and this number increased 2 ×108 tons every year. The characteristics of metal mine tails mainly include: (1) the grain size is extremely fine; (2) The quantity in weight was very large; (3) the toxicity is very strong; (4) Transporting concentration is very low. The migration of heavy metals would impact the local environment, the safety of the downriver resident and the plowland, the food safety of livestock as well as the solid’s safety. Based on the characteristics of mine tailings impacting to environment, this paper estimates the pollution property, as well as studies the harm for the outside environment through the experiment of the gross analysis and the infusion toxicity analysis. This research takes Longdu tailings of Dahong Mountain for example to know the harm of heavy metal ion.