Abstract: In a hydrogen peroxide（27.5%，mass fraction） production unit with 120 000 t/a producing capacity by anthra- quinone method，there existed several problems，i.e. low product concentration of hydrogen peroxide，high residual content of hydrogen peroxide in the extraction raffinate，and high alkali consumption etc..The key equipments and internals in the procedures of hydrogenation，oxidation，extraction，and alkali-treatment，were optimized and reformed.After reformation，the product mass fraction of hydrogen peroxide increased to more than 27.5% from the range of 20%～23%，the residual content of hydrogen peroxide in the extraction raffinate decreased to less than 0.15 g/L from higher than 0.30 g/L，the alkali consumption decreased to 3.4 t/h from 4.0 t/h.Both the economical benefit of enterprise and the unit operation safety were improved after the reformation.

Key words: anthraquinone method, hydrogen peroxide, optimization and reforming