The velocities of reaction of ethyl acetate with sodium hydroxide in dioxane-water mixture have been determined in seven different temperatures (5°,10°, 15°,20°,25°,30° and 35°).For each temperature, the compositions of solvent mixture are 0, 5, 10, 15, 20, 25 and 30% of dioxane. We thus obtain 49 velocity constants as summarized in the following table.