A quantitative structure–property relationship (QSPR) model was developed to predict the gas-to-ionic liquid partition coefficient of a set of diverse organic solutes dissolved in 1-(2-hydroxyethyl)-1-methylimidazoliumtris(pentafluoroethyl)trifluorophosphate ([EtOHMIm]+[FAP]−) at 323K using the replacement method (RM) and support vector machine (SVM). Several types of molecular descriptors were calculated to represent the molecular structures of the different organic compounds studied. The replacement method (RM) was employed to select the optimal subset of descriptors that makes significant contributions to the gas-to-ionic liquid partition coefficient (K) overall property. Our study revealed that the dependence of physico-chemical properties on partition coefficient is a nonlinear and that RM method is incapable of modeling it precisely. The results obtained, exemplify that, the calculated log K values by SVM method were in good agreement with the experimental data, and the performance of the SVM model was superior to RM one.