Abstract: To determine and calculate oxygen solubility in acetic acid-water mixed solvents, a set of apparatus for measuring gas solubility in liquid and a new model of calculating gas solubility in associated mixed solvents are reported in this paper.The apparatus could continuously be used to measure several solubility data under various pressures when solvents were fed once. The solubility of oxygen in acetic acid-water mixed solvents at 25—80 ℃ were determined with this apparatus.A new model of calculating oxygen solubility in associated mixed solvents of acetic acid and water was established. The parameters of the above model were correlated from the experimental solubility data by simplex optimization. The average relative error of calculation was no more than ±3.0%, so this new model could be used to calculate oxygen solubility in acetic acid-water mixed solvents.