Abstract: In this paper, a newnet primary productivity model of natural vegetation is presented, with a view to the ecophysiological feature and regional evapotranspiration model relating the two well-known balance equations on the earth′s surface: water balance equation and heat balance equation:This model will help us to study the potential productivity of zonal landscape, the regional and global distribution of NPP, to predict the possible impact of global change on terrestrial ecosystems, and to make good use of climatic resources.