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 basis of quantitative analysis in remote sensing with the appropriate method of acquiring the bidirectional reflective characteristic of objects in natural environment.For a long period

BRF（Bidirectional Reflectance Factor） acquired in natural environment and related to radiant environment

is regarded as the expression of bidirectional reflective characteristic of objects.There are differences which must be considered between BRF and real value except in a strict clear day.In order to eliminate the influence of the environment radiance

some method acquiring BRDF（Bidirectional Reflectance Distribution Function） data of objects in natural environment have been designed.But the error occurred in these method has not been strictly analyzed.In this paper these methods are compared by using radiosity-graphic combined model based on three dimensional structures which is one of computer simulation model.And their fixed error affected by conditions acquiring BRDF data is analyzed in the simulation.We also provide principles to choose the suitable method of acquiring BRDF data in natural environment.By these principles we can take the most suitable method under different conditions in order to reduce the error and get acceptable value from measurement.