This paper decomposes land use changes for GTAP-BIO-W model (Taheripour et al., 2013). For decomposing changes in land use, we take the accounting relationship and totally differentiate it. Land use in each region obtained by summation of land use in production of various crops in different AEZs in all river basins of the region. Then, corresponding variables for each of the component parts are introduced. Finally, these pieces are assembled according to the methodology developed by Huff and Hertel (2000) for welfare decomposition. Then any individual component is explored deeply to find out where the results are coming from.