Arsenic distribution characteristics in environmental media have been discussed in this paper.Arsenic distribution in the second soil environment is mainly attributed to man's activities,such as coal burning,mineral smelting and agricultural sewage dumping.Arsenic mainly exists in soil surface as stable minerals.Soluble arsenic is correspondingly high wherever the total arsenic content is high.Arsenic is likely to be fixed by iron,aluminum and calcium to form arsenides.When pH in soil rises to neutral or alkali,arsenic is easily transformed into tervalent arsenic which has stronger migration capability and toxicity.Arsenic is obviously harmful to crops and human beings. Arsenic in vegetables is more harmful than in corns.More effective measures should be taken to prevent and tackle arsenic pollution in soil.