Delimiting of key zones for soil and water loss control is an important work during soil and water conservation plan.It is different from delimiting of type zones for soil and water conservation with an important directive significat ion for recent conservation. With a case of Guangzhou city, based on comprehensive investigation of soil loss and correlative data, the key zones for soil and water loss control were delimited, including 4 key harness zones,3 key supervised zones and 2 protected zones. The control directions of everyone were also indicated.