Nowadays finding suitable places for establishing a landuse in a specific geographical subject is considered as an important step in applied projects, especially in macro and national level. Saxaul (Haloxylon sp) is one of the important and valuable plant species to preventing desert expansion that not only stabilize moving dunes but also is a suitable plant for biological reclamation and as a fodder providing source in deserts and arid regions. In recent decades saxaul has been planted in different places and so acceptable results is cuased in such cases. Unfortunately, in spite of immense expenditure, the difficulties in site selection criteria for saxaul planting on the one hand and difficulties in dicision making to selecting sites in complexity of environmental conditions on the other hand, result in unsuccessful plantations. In this research, it has been tried to develop an exact model based on Fuzzy logic and using suitable techniques, softwares and so previouse studies to select the planting sites for two Saxaul species (i.e. Haloxylon persicum and Haloxylon ammodenderon ). So, in order to find suitable sites for planting this two species, the environmental properties of their natural habitats considered as the optimum conditions. Then, the environmental parameters affecting their setting and growth, were studied and South Khorasan. From the climatic aspects, whole the area was suitable to Saxaul plantation, so the soil parameters were studied. Soil maps were produces usind interpolation methods such as Kriging and IDW. With the fuzzy logic evaluation and equipping ArcGIS 9.2 with Arcsdm 3 software, a simple model were developed to site selection of Saxaul planting. The Results showed that planting Haloxylon ammodendron in study area will be successful 40 to 70% in compare to the optimum condition of its natural habitats. And also 90% of the study area is not suitable for planting Haloxylon persicum . This species can only be planted in 3% of this area with a 30% succession probability again in compare to the optimum condition of its natural habitats. Kriging method in comparison to the IDW was success to anticipate the soil parameters interpolating with a higher precision. The final map resulted from overlying interpolated maps which were evaluated base on fuzzy logic for planting Haloxylon ammodendron compare to status of the mean canopy cover in hectar of the planted saxuals testified the succession of the model. Key words: Site selection, South Khorasan , Haloxylon sp , Fuzzy logic