A series of polysulfide-based polyureas with different siloxane contents were synthesized, and they were based on isophorone diisocyanate, liquid polysulfide oligomer, aminoethylaminopropyl poly(dimethyl siloxane) (AEAPS), and 2,5-diamino-3,6-dimethylmercapto-toluene. The mechanical and surface properties were investigated with attenuated total reflectance Fourier transform infrared spectroscopy, surface contact angles, electron spectroscopy for chemical analysis, and stress-strain analysis. Siloxane was enriched on the surfaces of these elastomers, and the tensile properties of the elastomers did not change markedly with the AEAPS modification.