This paper discussed environmental dredging engineering technology for sediment in lake, which is a new technique of the field in worldwide. The paper presented environmental dredging technique of lake sediment on the basis first environmental dredging engineering — Chaohei engineering of Lake Dianchi, including the nature of environmental dredging, technological process, main dredging facilities selection, the silt and its stockpile and dewater and treatment, as well measures to prevent pollution in environmental dredging. The technique developed is practical one to control pollution and eutrophication for Lakes all over the China.