In this work, the adsorption of DB2 dye on yttrium oxide (Y2O3) nanoparticles was investigated under various experimental conditions. The effect of temperatures and pH were studied, it was noted that the increasing in temperatures increases the adsorption quantity, which is increased in icidic medium and decreased in basic medium. The isotherm models ( Langmiur, Freundlich, Temkin, Halsey and Harkins-Jura) were applicated and the isotherms can be arrange according to its high correlation-coefficients as follows: Freundlich (0.969) > Harkins-Jura (0.957) > Halsey (0.944) > Temkin (0.942) > Langmiur (0.902), the Freundlich isotherm model is suitable for the adsorption process. Thermodynamic Parameters such as ΔH, ΔG and ΔS were calculated from the slops and intercepts of the linear variation of lnk against 1/T, where noted that the adsorption of DB2 dye on Y2O3 nanoparticles is ( endothermic reaction)