Net primary productivity (NPP), as the basis of ecosystem material and energy cycle, can reflect the carbon sequestration capacity of vegetation at regional and global scales, and is an important indicator to evaluate the quality of terrestrial ecosystem. Based on the principle of light use efficiency model, the productivity model of ecosystem in national barrier area was established by coupling remote sensing, meteorology, vegetation and soil type data. In the selection of parameters, the photosynthetic effective radiation (APAR) was calculated from GIMMS NDVI 3gv1.0 data, vegetation map of China, total solar radiation and temperature and humidity data. Compared with the soil water molecular model, the regional evapotranspiration model can simplify the parameters and enhance the operability of the model. The net primary productivity (NPP) of terrestrial vegetation in 1990-2015 over the Qinghai Tibet Plateau was estimated based on the parameterized model with par and actual light use efficiency as input variables of CASA model.