The simulation of net primary productivity (NPP) in terrestrial ecosystem comes into a stage of process-based simulation from statistics-based simulation.We review the history of study on NPP in China;it has made a rapid progress.However,we should pay more attention to study on NPP modeling.Process models for estimating NPP simulate a series of plant physiological processes.Process models have the advantages of: (1) being theoretically grounded, (2) the ability to handle interactions and feedbacks of different processes, (3) the flexibility to describe details of biological processes under a variety of conditions, and (4) the verifiability of explicit hypotheses regarding plant physiological processes.Furthermore,process models based remote sensing will simulate and monitor dynamically NPP of terrestrial ecosystem timely,macroscopically,exactly from multi-scale,though the NPP temporal-spatial change pattern will be shown well.We expound every kind of process -based model from leaf scale,canopy scale and region scale.Because of complexity and heterogeneousness of ecosystem,it is an important question to scale in NPP modeling.We could complete scaling by mathematic method.And remote sensing and GIS provide a new way to scaling.