Abstract: Water loss is the basic form of soil and water loss. Technical terms in national standards is the theoretical foundation of researches in this regard. In view of the current water loss theory, the concept of water loss in national standard technical terms needs to be revised. The connotation of water loss is expounded from three respects runoff, evaporation and infiltration. The basic content of water loss prediction, control measures and monitoring are presented. This research could be a reference to improve regulation standards and prevent soil and water loss.

Key words: soil and water loss, water loss, technical terms of soil and water conservation, new concept of water loss