Wetland evapotranspiration is the major way of wetland water loss. It has attracted widespread attention because of its high sensitivity and important effect on climate change. Wetland evapotranspiration process can be divided into multiple scales including leaf,plant,canopy, landscape,region,etc. How to realize the coupling of processes and parameters at different time and space scales is one of the emphases and difficulties in wetland evapotranspiration research. This paper reviews the development of evapotranspiration simulation on wetland. The monitoring and simulation methods of reed wetland evapotranspiration are summarized from different time scales (such as daily,monthly,yearly) and different spatial scales (such as leaf,plant,canopy, region). The key technologies about how to expand different time and space scales are also summarized,and then the major research in future is discussed. Coupling parameters in atmosphere-vegetation-soil interface is the key to accurately simulate the evapotranspiration at different time and space scales in reed wetland. At present,there are few researches on the reed wetland evapotranspiration parameterization at different scales. Therefore,to explore the methods of evapotranspiration modeling and parameterization can provide theoretical supports for the choice of evapotranspiration assessment models of reed wetland.