Leaf area index （LAI） is an important parameter for describing vegetation canopy structure in the terrestrial ecosystem. LAI can be obtained using spectral information such as simulated relation of VI（ vegetation index）

however

many VIs are affected by soil. For row crop

it is difficult to remove the effect of soil

and the error is large using the method of VI. Multiangular remote sensing is capable of providing more three-dimensional information of vegetation

and it is powerful in obtaining the parameter of the plants. However

currently

the retrieval of multiangular remote sensing seldom considers the use of spectral information. We use MSAVI2 as an index to get the a priori knowledge of LAI. As a result

the a priori knowledge is more objective. From the comparison of using or not using this MSAVI predicted a priori knowledge

we found that this approach is effective.