The bidirectional reflective characteristic of objects plays an important role not only in models of remote sensing but also in inversion

consequently

it is the base of quantitative analysis in remote sensing that chooses the appropriate method of acquiring the bidirectional reflective characteristic of ocjects in natural environment.For a long period

BRF（Bidirectional Reflectance Factor） acquired in natural environment is taken as the expression of bidirectional reflective characteristic of objects

but the definition of BRF doesn’t prescribe radiant circumstances explicitly.Actually

BRF acquired in natural environment is related to radiant environment

so it is unsuitable to describe the reflective characteristic of objects with BRF.This viewpoint is testified in this paper by field data

meanwhile

we established the truth that BRDF（Bidirectional Reflectance Distribution Function） has nothing to do with the radiant environment.This paper provides a new method of acquiring BRDF data of objects in natural environment in order to arouse more pondering over the difference between BRDF and BRF.As it is indicated in the result of the experiments

with this method

we can acquire BRDF of objects in natural environment exactly.