Abstract: In the hydrogen peroxide industry in China，the vacuum dehydration process has not got the deserving attention for a long time，because it cannot regenerate and clean the working solution，and the research about the principle，process conditions，and the advantages and disadvantages of the vacuum dehydration was lacked.The principle of vacuum dehydration in hydrogen peroxide device was analyzed.The causes of the differences between the theoretical value and practical value of working solution vapor pressure，and the differences between the theoretical value and the actual value of gas phase composition content were given.The views that the free water content was higher than the dissolved water in the working solution was put forward，and the suitable temperature of 52 ℃ and the pressure of 10 to 12 kPa in vacuum dehydration were calculated and determined.Finally，it also proposed that vacuum dehydration was far superior to alkali tower dehydration in dehydration effect， safety，and cost etc.，and the regeneration and cleaning functions could be effectively replaced by inhibiting the degradation materials.

Key words: hydrogen peroxide, vacuum dehydration, alkali tower dehydration