Abstract: Seven different density functional theory methods have been employed to predict the molecular structures and adiabatic electronic affinities of RS/RS^-(R=CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, n-C₅H₁₁, i-C₃H₇, t-C₄H₉) radicals and their anions. The basis used is of double-ζ plus polarization quality with additional s-and p-type diffuse functions, labeled as DZP+ +. The most reliable adiabatic electron affinities, obtained by B3LYP methods,are 1.838eV (CH₃S), 1.925eV(C₂H₅S), 1.939eV(n-C₃H₇S), 1.961eV(n-C₄H₉S), 1.969eV(n-C₅H₁₁S), 2.023eV(i-C₃H₇S), and 2.055eV(t-C₄H₉S), respectively. Compared with the experimental values, the average absolute error of the B3LYP method remained only 0.047eV.