Abstract: The solvation effects of organic soivcnts(methol alcohyl,ethyl alcohol,n-propanol, isopropanol, acetone, dimethyl sulfoxide, dimelhylformamide and dioxane)on colour reactions of multicomponcnt complex (MCC) of scandium with chromazurol-S(CAS) and long chain cation surfactants have been systematically investigated.The sensitivity and selectivity of the colour reactions of MCCof scandium can be markedly improved by the solvation effects of organic solvents. The molar absorptivity of the complex Sc-CAS-OtTABis 1.4× 10⁵ l/mol·cm in the absence of organic solvetn, but it (e) can be risen to 3.2× 10⁵ l/mol·cm in the presence of methyl alcohol or dimethyl formamide. The new highly sensitive and selective colour reactions have been developed as a method for the determination micro amounts of scandium in rare earth oxide and in fcrritc of lanthanum and scandium. The composition of MCCof scandium and its solvation number were determined. The mechanism of the solvation effect has been discussed.