It’s a primary question for many Bi directional models of Canopy presently that it’s difficult for them to be used in practice due to their complexity. In this paper

multi scatterings and transmission taking place in canopy of vegetation

and reflectance of soil are analyzed respectively

and then the functions between every component of scattering and LAI are put forward. Improving Verstraete’s（1986） Physical Model of Bi directional Reflectance of Vegetation Canopy by adding multi scattering and soil reflectance in the model

a Bi directional reflectance model of canopy soil as proposed and it was proved that the model’s precision can be satisfied only when the first three scattering being taken into account. The shortcoming of the original model has been overcome in this model

and Bi directional reflectance can be calculated directly according to LAI and some other factors

avoiding overlap calculation which results tremendous amount of computation

so the model is easier applied in practice. The precision of the model was verified by experiments.