Abstract: The aim of this research was to investigate the inactivation efficacy of chlorine dioxide on Saccharomyces cerevisiae 1450 in water, apple juice and on apple surfaces. Results showed that the population of yeast in water reduced (5.81±0.12) and (6.20±0.05)lg cfu/mL when they were treated with 6, 12 mg/L of ClO₂, respectively. The inactivation efficacy of 100 mg/L of ClO₂ was not distinct in apple juice. The yeast initially inoculated in apple juice (3.79±0.04)lg cfu/mL was completely inactivated treated with ClO₂ of 200 mg/L for one hour. While the yeast initially inoculated in the apple juice (6.48±0.03)lg cfu/mL reduced (3.67±0.05)lg cfu/mL with the same treatment. Treatment with ClO₂ of 300 mg/L for one hour completely inactivated (6.52±0.06)lg cfu/mL of the yeast initially inoculated in apple juice. The yeast initially inoculated on apple surfaces (4.95±0.02)lg cfu/mL reduced (3.41±0.02), (3.64±0.08), (3.80±0.04) and (4.47±0.09)lg cfu/mL when they were treated with ClO₂ of 10, 20, 30 and 40 mg/L, respectively; while it can be completely inactivated treated with ClO₂ of 50 mg/L for one hour. The inactivation efficacy of ClO₂ on the yeast would be decreased with the increasing population of yeast inoculated on apple surfaces. The treatment of ClO₂ had less influence on phyisical and chemical indexes of apple juice.