It) is fundamental to calculate photosynthesis of terrestrial vegetation quantificationally for estimating agricultural and terrestrial ecosystem net primary productivity.In this paper

some methods of observing CO

2

flux and some problems of scaling on geography in the world are reviewed briefly

and stomata conductance model and photosynthesis model are analyzed in detail.At the same time

four kinds of upscaling models from leaf to canopy（big-leaf model

multi-layer model

two-big-leaf model

and multi-layer-two-big-leaf model） and some upscaling methods from canopy to community are summarized at length.Advantages and disadvantages are analyzed for all the models and methods

through which a conclusion was drawn that the key of the success in remote sensing researches is how to select suitable models and parameters according to different objects.