Abstract: To develop a more suitable method for oxidative decoloration of reactive dyes,the oxidative decoloration of 3 kinds of reactive dyes existing in dye effluent and colored textiles was carried out by chlorine dioxide(ClO_2).The results of decoloration were examined by using UV-Vis spectrum and colour measurement and matching instrument.They indicated that ClO_2 has exhibited rather good decoloration effect for dyes existing in aqueous solution and colored textiles at atmospheric temperature and pressure.After(1 hour′s) treatment with chlorine dioxide,the decoloration rate of the 3 kinds of dyes in the effluent is more than 95%,and the K/S value of colored textiles decreases evidently,this provides a new thinking for decoloration of colored textiles.