The hydroxyl-terminated poly(dimethylsiloxane) (PDMS) was used to measure swelling equilibria for solvent(1)/PDMS(2) and solvent(1)/solvent(2)/PDMS(3) systems. PDMSs were vulcanized to prepare four compounds (PDMS-35, PDMS-40, PDMS-45, and PDMS-50) having different hardness. The swelling ratios of the binary and the ternary systems mere measured and supplied at various temperatures from 303.15 K to 318.15 K. They were used to describe the swelling abilities of the cross-linked PDMS absorbing mixed solvents into the polymers. A Flory-Huggins model was combined with three different expressions to describe swelling equilibria of the binary and the ternary systems. The experimental swelling equilibria data were correlated with the models to estimate the Flory-Huggins (FH) interaction energy parameters and the average molecular weights of chains between the cross-linked PDMS. The swelling behaviors of the cross-linked PDMSs were described by the FH interaction energy parameters.