Abstract: An apparatus and corresponding experimental procedures for accurate and rapid determination of both vapor pressures of pure or mixed solvents and gas solubilities are presented. The solubility data of hydrogen in the binary mixed solvent, acetonemethyl isobutyl ketone (MIBK) and the vapor pressures of the solvents at 293.15, 298.15, 303.15, 308.15, 313.15, and 318.15 K are reported. Based on Hu and Xu's theory, a new method has been developed for the correlation of gas solubilities in the mixed solvents, where the difference between the interactions of the solute with different solvents is considered by introducing the concept of the local number density. The theory works well for the correlation of many literature data, 46 systems in all including Ar, H_2, O_2, N_2, N_2O, CO_2, C_2H_6, etc. in both nonpolar and polar mixed solvents, as well as the experimental data reported in this paper.