The quantitative structure-property relationship (QSPR) of extractability of sugars with phenylboronate and quaternary ammonium salt was studied using molecular modeling with semi-empirical molecular orbital calculations considering solvent effects (SMO-COSMO method). The QSPR of the complex formation between sugar and phenylboronate in water was examined. Since plots of the QSPR gave good linear relationships, the stability of complexes formed between phenylboronate and sugars in water is predictable based on the plots. However, sugar structural isomer (furanose or pyranose) involved the complex formation in water could not be determined by the molecular modeling. In the presence of organic solvents including phenylboronate and quaternary ammonium salt, the QSPR of the complex formation with sugars in the organic solvent was examined. Although experimental results obtained in previous studies show that the selectivity of sugar extraction depends on the quaternary ammonium salts used, the calculated results could explain well the difference in the selectivity between trioctylmethyl ammonium chloride and trimethylhexadecyl ammonium chloride. The QSPR also allows quantitative prediction of the extraction equilibrium relation in organic solvents with molecular modeling using the SMO-COSMO method. Thus. with the aid of computational chemistry, it is possible to predict quantitatively the complex extraction behavior of sugars with phenylboronate and quaternary ammonium salt.