Abstract: Chemical-biological sand fixation is an effective technology for sand control. In order to understand the effects of sand fixation chemicals on biodiversities of plants and microorganisms, this study investigated treatments such as 450, 600, 750 kg/hm² chemical and took no chemical treatment as control, and analyzed the biodiversities of plants and microorganisms. The results showed that after application of chemical, the importance value of community increased as dominance. The height, coverage and biomass increased in all treatments except control, which indicated that sand fixation chemical had an improving effect on growth of community and treatment of 600 kg/hm² had the best effect. As the application amount increased, the biodiversity of plants and microorganisms both decreased, however, the dominance both increased. There was a linear correlation between diversity of plants and microorganisms, as well as the dominance. Plants influenced the soil environment and then had an impact on the structure of microorganism community and its biodiversity.