(1) The rate of solution of oxygen into sodium sulphite solution of various concentrations was observed by the measurements of the decrease of the volume of gas phase at constant temperature and pressure. (2) At low concentrations of sodium sulphite solution, the rate of solution of oxygen increases as the concentration of sodium sulphite increases. At middle concentrations, the rate of solution is maximum and independent of the concentration of sodium sulphite. At high concentrations the rate of solution decreases with the increase of the concentration of sodium sulphite. (3) A theoretical interpretation on the results of the present experiments was given.