Phase diagrams of the aqueous two-phase system N-ethylpyridinium tetrafluoroborate + sodium succinate/ammonium citrate + water were experimentally determined at 308.15 K, 318.15 K, and 328.15 K, respectively. The binodal data and tie-line data were associated with numerous empirical formulas and good agreements have been obtained. The effect of salt type and temperature on binodal curves and tie lines were emphatically discussed via observing the phase diagrams and analyzing the correlation data. It was found that there were significant differences between the two salts when they were constructing two phases with N-ethylpyridinium tetrafluoroborate. The effective excluded volume values used to evaluate the salt-out effect of two inorganic salts were derived from correlating the experimental binodal data of investigated systems.