The kinetics of sucrose hydrolysis was investigated in a water-ethanol mixture with ethanol concentrations of 0–80% (v/v) under subcritical conditions in the 160–190°C range. Sucrose underwent autocatalytic hydrolysis in the subcritical mixtures. The rate of sucrose hydrolysis to glucose and fructose was reduced with increasing ethanol concentration, and ethanol showed a dilution effect on the conversion. The temperature dependence of the reaction rate constant for sucrose hydrolysis obeyed the Arrhenius equation. The fructose and glucose products underwent further decomposition, and the yield of fructose was much lower than that of glucose when the ethanol concentration increased. Thus, ethanol exerted other effects on the reaction in the subcritical water-ethanol mixture.