According to a lot of hydrological and environmental monito ring data,the condition of soil and water loss in Lancang river watershed is ex pressed.The occurrence and development of it are a nalysed.The conclusion is that,(1) Generally,the co ndi tion of soil and water loss is light,however in some region,which is serious,especially in the middle reaches of the river.(2) The soil and water loss in Lancang river watershed presents the developing tendency and it is mainly caused by human activities.In accordance with those results,the control measures fo r soil and water loss are discussed.