It’s a widely studied field to get the structural parameters of the vegetation with remote sensing data. In this paper

multi-spectral information is used in the multi-angular remote sensing research. A spectral-directional reflectance remote sensing model of regional-scale is presented for the semiarid grassland. Starting with the Geometric-Optical modeling and considering the difference between the tree and the grass

two most important scene elements are accounted for in this model: bare soil and canopy. The model is composed of the Multi-spectral Reflectance Model（MSRM） for calculating the canopy reflectance

the soil spectral reflectance Price model and the soil BRDF Walthall model for calculating the soil reflectance. Poisson model is used to calculate the percentage of each component of remote sensing pixel. Validation has been done using MISR and MODIS data for the model. The result shows that RMS between modeled multi-angular reflectance and MISR data

and RMS between modeled multi-spectral reflectance and MODIS data are 5.31%

6.37%

4.69% and 5.14%

4.68%

5.71% for no degraded grassland

slightly degraded grassland and badly degraded grassland respectively. The precision of our model can meet requirement of research work.The sub model of soil reflectance is experimental. The study has shown that it can be replaced by the mechanism model

for the percentage of soil is dominated especially in the badly degraded grassland. In conclusion

it provides a new approach of application of remote sensing apllication to quantitative study and quick evaluation of grassland degradation in the semiarid region.