In multiangular remote sensing observations,the variable range of the solar zenith angle (SZN) is narrow.We takes the linear kernel-driven model as an example to analyze the parameter error propagation in inversion by using the observations at single sun position and to show that in such case it is unreliable to invert the BRDF tendency with SZN.To improve the algorithm,we suggest adding certain constraint for the changing trend of albedo with SZN in the model inversion.