Abstract: In order to reduce the impact of chromaticity on salt chemical products and to increase the added-value of bittern products，the paper studied the removing effect of coloured substances in the bittern of salt lakes by hydrogen peroxide oxidation method based on the physical and chemical characteristics of the bittern.The study result showed that the optimum conditions of decoloration by hydrogen peroxide oxidation method were：adjust the pH value of bittern to 2，the dosage of hydrogen peroxide is 3% (mass fraction)，then heat up the mixture to 40 ℃ with agitation for 2 h.Under such conditions，the decolorizing rate of bittern can reach 60%.After decoloration，the color strength of bittern had obviously declined and the bittern became more transparent.Through analyzing the variation of the apparent molecular weight of organic substances in the bittern around oxidation time，it was found that the proportion of the organic substances whose apparent molecular weight larger than 30 ku increased，while the proportion of the organic substances between 3~30 ku decreased after decoloration.