在前人研究的基础上 ,建立了水稻光合 蒸散耦合模型 (PE模型 ) ,其主要特点是 :①改进了Monteith的蒸散模型 ,使之由“大叶”模型成为群体分层结构模型 ;②通过提出阻风系数概念 ,建立了一系列可模拟群体中各叶层风速、边界层厚度、边界层阻抗、湍流交换系数、群体动力阻抗等要素的子模型 ;③应用群体光合作用模型和改进的Ball公式 ,将以上各要素连接起来 ,实现了光合模型与蒸散模型的耦合。利用PE模型 ,分别模拟了水稻前中期与后期不同株型的群体光合量、蒸散量以及水分利用效率。结果表明 :不论在前中期或后期 ,都以“上挺下披”株型的水分利用效率为最高 ,因为这种株型不仅光合量最高 ,而且蒸散量较小。PE模型模拟出的水稻蒸散的作物系数与实测值之间有良好的一致性 Based on the previous studies, the model of photosynthetic evapotranspiration (PE) was established. Its main features are as follows: (1) Monteith’s evapotranspiration model has been improved to make it a group hierarchical model by “big leaf” model; (2) A series of sub-models that can simulate the wind speed, boundary layer thickness, boundary layer impedance, turbulence exchange coefficient, population dynamic impedance and other factors in the population can be established; ③The population photosynthesis model and the improved Ball Formula, the above elements are connected to achieve the coupling of photosynthetic model and evapotranspiration model. The model of PE was used to simulate the photosynthesis, evapotranspiration and water use efficiency of different plant types in the early and middle stages of rice. The results showed that the water use efficiency of “Shangtixiaitiao” plant type was the highest in either the middle or late stage, because it had the highest photosynthetic rate and the smaller evapotranspiration. There is a good agreement between the crop coefficient simulated by PE model and the measured value of rice evapotranspiration