Validation is one of the most important processes used to evaluate whether remotely sensed products can accurately reflect land surface configuration. Leaf Area Index（ LAI） is a key parameter that represents vegetation canopy structures and growth conditions. Accurate evaluation of LAI products is the basis for applying them to land surface models. In this study

validation methods of coarse resolution MODIS and GLASS LAI products for heterogeneous pixels are established on the basis of the scaling effect and the scaling transformation. Considering spatial heterogeneity and growth difference

we transformed LAI from field measurements into a 1 km resolution scale with the aid of middle resolution images. We used average LAI and apparent LAI separately to validate the algorithms and products of MODIS and GLASS LAI. Two study areas

Hebi City and the Yingke Oasis

were selected for validation. Both MODIS and GLASS LAI products underestimate the true LAI in crop area. However

this result cannot be completely attributed to their algorithms. Instead

the primary reason is the heterogeneity and nonuniformity of the coarse pixels.Underestimation is evident in the Yingke Oasis

where heterogeneity is significant. Given that GLASS LAI product is the fusion of multiple LAI products

the mean value of this product is closer to the real situation

but the dynamic range is narrower than that of MODIS LAI product.