Nutrient deficiency is one of the main factors that influence plant productivity in agriculture and forestry. Fertilization and soil improvement are the major for meeting the nutrient of crops in traditional agriculture and forestry management. Recently plants with high nutrient use efficiency (NUE) have been discovered to replace the traditional measures for improving the NUE of crops. Long-term evolution and environmental adaptation has resulted in significant differences between the NUE of different plants or different genotypes of a plant. It is extremely important for scientists to find genotypes with high NUE. However, different researchers have different understandings of the concept of plant NUE, which results in difficulties in comparing of research results. From s reasoned analysis of the NUE concept and formulation of a unified description, it is suggested the NUE of a forest plantation should be expressed as the ratio of the biomass of stemwood to the total nutrient content of the plantation. The biological and physiological adaptation mechanisms of high NUE plants are reviewed and the nutrient adaptive responses to stress of plants with high NUE are described. The biological function of Ca2+ within the mechanism of high NUE is demonstrated, which indicates that Ca2+ was the main regulatory factor for plant chemical communication. Finally future research in this field is proposed.