Chitosan is a natural biopolymer that is used in this research to improve the geotechnical properties of desert sand due to its cementation properties. In the present study, by conducting unconfined compression tests, direct shear and electron microscopy tests it is shown, that this material can be considered as an appropriate alternative for soil stabilization. The results of unconfined compression tests on samples with 0.5, 1, 2, 3, 4, 5, 6, 7 and 10% chitosan, show that with increasing chitosan content up to 7% shear strength increasing significantly, however an increase of more than 7% in chitosan content, reduces shear strength. The results of tests with 1, 3, 7, 14 and 28 days curing process duration and also at different temperatures of curing indicated that 14 days duration is enough for sample preparation and 60 ° C is the optimum temperature for curing of the samples stabilized with chitosan biopolymer. The results of the direct shear test show that the effect of this material on the cohesion of the sandy soil is significant, as with the increasing of 1 and 2% chitosan cohesion increased from 13.6 to 106 and 156 kPa, respectively. Finally, electron microscopy images are used to investigate the morphology of chitosan stabilized samples.