Abstract: Holdridge′s Life zone classification system is highly evaluated by international circles of ecolgy and environmental sciences owing to its simple and convenient for calculation and better correspondence with vegetation types. Recently it has been especially applied to assess environment, engage in ecological regionalization,predict the impact of global change upon ecosystems, etc. The result of analysis of climatological date for vegetation zones in China by means of Holdridge′s system also shows a significant correspondence. But, because it was developed in the tropical zone of Central America, an adjustment in China′s subtropical zone is needed. Nevertheless, the application of that system should be beneficiate for unification and comparative study of the climate-vegetation interaction in the world. The regression analysis shows a significant correlation between Holdridge′s potential evapotranspiration rate (PER) and radiative dryness index (RDI) of Chikugo Model. Therefore, PER could be used to estimate Net Primary Productivity (NPP). Its result of calculation for vegetation zones in China is satisfied and could be used to predict the change in vegetation zones, main types of ecosystems, and NPP in China.