Abstract: For investigating the dyeing mechanism of the natural dye—Scutellaria baicalensis Georgi on silk fiber and improving the dye up-taking control,dyeing result prediction and dyeing process optimization,the absorption equilibrium experiments of silk fiber were carried out by pre-chelating with aluminium ions,then dyed with Scutellaria baicalensis Georgi′s extract-baicalin,and three theoretic adsorption models,i.e.,Langmuir,Freundlich and Nernst isotherm were used to simulate the experimental data at the temperature of 30、45、60 ℃.Some dyeing thermodynamics parameters of baicalin on silk were studied.The results indicated that the kind of adsorption belonged to Langmuir model proximally,and the adsorption model was validated by the simulation coefficients and normalized deviations.The process was endothermic with the dyeing heat ΔH =2.303 4 kJ/mol,and the dyeing entropy ΔS=6 J/mol.In addition,the dyeing affinity and saturation absorption capacity increased as the temperature increased.